I've recently completely turned this mower into a new build. If you've read this before, proceed to step 12 for the latest updates. Otherwise, start reading below for the original build. Thanks to everyone who has commented before. As always, feel free to ask questions and I'll do my best to answer. Click Here to proceed to step 12.

In this demo, you'll get some ideas of how you can make a real racing riding mower used in national events. Have fun turning what used to be the family lawn mower into a fire-breathing high speed racing machine. Also- I'm constantly making changes and modifications to the final machine so check back to see what I've done. The next plans I have include steering upgrades.

Please read the following paragraph before proceeding.

Before we start, there's a bit of safety to discuss.Yes, racing lawn mowers from an outward perspective is sort of funny ( which it is!)But its important to realize that racing mowers such as these are heavily modified to handle much greater speeds than the original mower was designed for. Many of these mowers go 50MPH or more.Making a race mower isn't as simple as taking a stock tractor and making it go fast without any alterations. So its important that the frame, brakes, steering, engine, and wheels are modified or altered to handle this additional speed.So to make this point doubly clear, it is NOT a good idea to take a bone stock mower and make it go fast. You can, and will get hurt if you do so, and trust me- I've seen enough people wreck due to this very reason. So play it safe. Secondly, if you do plan on racing, make sure and check out the rules for your chapter and wear appropriate safety gear such as a helmet ( motorbike), gloves, boots, and long pants.My mower is built using ARMA ( American Racing Mower Association) rules and regulations. Lastly, your mower must have an approved jet ski/snowmobile style safety tether switch. If you fall off ( which we often do) the mower must automatically shut down or it'll keep right on going! Racing mowers might seem silly, which it sort of is, but you can get hurt if you're not careful. So be safe!

Ready, let's get started! The 'victim' I chose for this build is a late 60's Grants mower. Tiny little mowers like these were produced back when riding mowers were still deemed a luxury. They're little more than a seat sitting on top of a mower deck. Most used smaller engines. The advantage of using such a little mower is that you can reduce the weight dramatically by simply having a 'legit' riding mower complimented with a larger engine, hence a higher power/weight ratio. Don't get attached to it. When its done, there won't be much left of the original.

The first step is to strip the mower down to the frame. Modern mowers usually have a single stamped piece of steel. Older mowers like this one have frames made of square tubing or slabs of steel. This will give you an idea of how much of the mower is actually usable and how you can lay out the drive, steering, and brake components. Besides the hood, what's leftover to use isn't much. The rest are worthless such as the stock wheels, steering wheel, and transmission.
Remove these adsRemove these ads by Signing Up
TraceD126 days ago
well it is 2015 no one has answered me maybe this will help someone in the future just by reading. If you're looking at buying a lawn more to turning it into a racing one this is what I have done. first off find you A MTD mower or another more that the pulleys are held on by a bolt not pressed on its just a much simpler process however you can get the press on pulley type if you have a pulley puller. I remove the 7.5 pinch pulley from the rear hi then installed a 2.5 inch pulley and the rear then I pulled the front pulley off cut the smaller pulley that is on top but just the upper neck off. the 7-inch that was in the rear I welded it to the front pulley and reinstalled it. yes know once you do this you will have to readjust v clutch linkage actually make it slightly longer. I also adjusted the governor up 450 rpms. I removed the front wheels the small hole in the center that allows it to pivot I cut it off clean reinstalled drill new bolt holes the whole the fun together in the rear I simply cut part of the main frame out to drop it three inches in the rear then 're-forced the metal. I managed to hit 40 miles per hour one time for the most part 33 to 35 miles per hour therefore I am going to take the front pulley off once more weld a 9 inch to the front and see if that will get me a consistent 40 to 42 miles per hour. just remember keep the wheel hub assemblies greased make absolutely sure you lower the lawn mower at high speeds these things are very unstable though it may look stupid I wear a helmet and a jackethopefully this will help someone in the process of them doing their first build. by the way if you build it correctly trust me you will need a wheelie bar.
TraceD1 made it!28 days ago
I have never build a racing lawn mower this is my first attempt, I have spent the last two days and approximately $50 building my lawn mower. I have a MTD, with a 17.5 horsepower motor I put a 2.5 inch pulley and the rear and a 7.5 inch pully up front. I had a friend of mine up the RPM's by 450. I lowered the rear 3 inches and the front 2 inches. this is a 6 speed on the go by the way. I am running 20x8x8, tires in ther rear my 2 questions I have do they make a 24x8x8 tire and does the muffler really restrict that much? I do have a wheelie bar on it today on the test run I was able to hit 40 miles per hour on GPS. thank you, oh and I have a kill switch lanyard on it as well.
ZOMBIE13131 month ago

Few comments for others reading this. First check with the organization u plan on running with to get rules before building. Some don't allow centriinjectclutches and use a gear transmission.

As far as porting and polishing, my teacher in tech school raced and built engines for motorcycles, snowmobiles and go carts. He taught that polishing the exhaust is fine. The intake side can be sanded after porting, but not polished. A slight roughness on the walls will cause a slight turbulence in the in coming air, which will help the air and fuel mix together (atomize). If smooth, no turbulence and possibly an air fuel mix that's not fully atomized and the fuel could separate from the air. That's why fuel injection works so good.

Put some grease or cam assembly lube on the valve spring retainer clips to hold them on the valve when assembling. If using the hammer and socket method to disassemble the valve springs, put a rag over top to help stop the retainers from flying and a rag under the valve head will hold the valve from moving and let the spring compress.

Wasn't talked about here, but always lube the cam lubes and bearings with assembly lube (STP oil treatment works too) when assembling engine.

Hope this helps some of u out.

Im working on building a race mower and im wondering how the build will cost

Go in a class that runs stock engines. After a year or two u should have the bugs worked out of the mower and be ready for more power.

Depends how crazy you go on it. I spent $1000 build a mower, and that wasn't anything fancy. As well, since I went with fairly cost effective solutions it did not adhere to racing lawnmower specs so it can't actually be raced, however that was never my intention so that was alright.
miller03051 year ago

What kind of welder will work for welding on the frame?

All types will work. If u don't have one and are looking to buy one, I would suggest a 110 volt portable wire feed. I have a Hobart 140 (made by Miller) which can weld with gas (cleaner weld) or flux core wire and weld sheet metal and steel up to 1/4". If u want a different brand, just get a similar size and type. Also if u buy the flux core wire, spend a little more and buy the better wire from a welding supply shop. Have had problems with wire sticking in tip with cheaper wire.

redneckcity973 months ago

I have a yard machines shift on the go riding mower that I want to turn into a racing mower. I want to know how fast I will go with an 11hp briggs and Stratton engine, a 8.5 engine pulley, and a 5.5 axle pulley. and I have a video of it on youtube. here is the link


yard machines shift on the go.jpg
beenie6 years ago
Where did you get your RAGB from? and how much did it set you back?
mowerracer (author)  beenie6 years ago
I got mine from Ebay. I have two of these, one as a spare. The first one was $30. The second was $50. They seem to be getting a bit harder to find. The cheapest are older RAGBs for riding mower decks. They typically have 2 bolts, but that will work fine.

what are your RAGB's off of exactly if you know. or even better how do you find them?. Everyone I fine is over a hundred dollars.

A brilliant build brilliantly explained. Love the stripped down raw appearance, this thing looks like it would absolutely fly! This might be of interest for those following this post http://lawnmowerwizard.com/featuredarticles/worlds-fastest-lawn-mower/ it's frankly ridiculous!

When you upgraded the stock starter to a high torque model, how did you determine which one to buy? I have a Tecumseh 36680 starter that needs to be replaced and am wondering if I should upgrade it to a better version. Here is the stock:

where did u find/get a high torque starter? i have a couple of racing mowers myself. thank u in advanced. :-)
75chevyk106 months ago
I was wondering what brand of clutch you have or recommend for using and how wide is you're axle
buskrat7 months ago
One thing I didnt see you make any mention to. But there was a pict of it modified in one picture was the crank case breather? Do you over size this at all? I know this is done on alot of race cars but wasn't sure if you had done anything with it
jeremy.rado.17 months ago

where did you buy most of your parts (brake, clutch, ect..)

I have been told you have to watch where you take meat off inside the head when your porting a head. I have heard this can actually make the engine put out less power if not done just so. Is this true ? Do you have to be expert at it , or just know the basic goal ?

You also mentioned you wasn't sure of the gear ratio. To figure the gear ratio you simply take the larger gear which i think you said yours was a 40 an divide the smaller clutch gear 14 thus giving you a 2.86 gear ratio.
If you decide to up your cam to a performane cam check out dyno cams they work great easy to set up an they will be glad to help you with your timing valve springs and differnt spring tensions as all this will play a role with an aftermarket cam. I would also suggest investing in a dagree wheel if your modifing yourself your going to need one. BMI karts is also an excellent kart shop to buy any frame components you may need in the future affordable prices. Turk bros. For any of your engine parts. I have built many karts an racing engines over the years an these places work well for service an price. I wish you the best hope this may help out. Feel free to email me with any engine questions b glad to help.
FredB29 months ago

how did you connect the engine to the gear box, do you have pics on that

if you put a 9 inch pulley on the front and a 3 inch on the back you would have to custom your belt but how fast would that ratio go 9:3

nishant2210 months ago

I wan to make a electric car for mech project I need a dc motor less than equal to 3000 w max rpm 3600 max torque 12.8nm at 2400 rpm power consumption max 48 volt can u recomend me some motor name or link which would suit best for me....thanx in advance...

I am not sure which is more impressive; your project or your very excellent narrative. My compliments on both efforts.....

My uncle has a 340cc 4 stroke and my dad has a 370cc 2 stroke which one
Should I use and I am using one of these engines
For racing can I have some
What kind of engine and what size did you use
For your mowers
Depends if you actually want to race it in mower racing competitions or just use it as a hooligan tool. Racing there are very specific rules you have to follow to be able to compete, and you would have to research these as there are several race types based on modifications, engine displacement, etc. If you are using it as a hooligan tool, you can do whatever you want. I used a 340cc twin 2 stroke from an older snowmobile running around 40hp which worked quite well. Using a non-stock engine to your tractor is more difficult though because you need to modify the drivetrain. I had to completely machine a new system for mine, brackets welded on for bearing supports, shafts machined, sprockets, chains. Real pain in the ass was odd sized shaft needed for the secondary clutch. The stock engine is best to go with in my opinion.
How many mowers do
You guys have?
Hay I'm a ten year old
Kid and I always wanted
A Lawn tractor do any
Of you guys/girls now
Anybody in Nova Scotia
With a lawn tractor for sale
Let me know Thanks
IT-Jack1 year ago
how to fast does it run?
This is a great Instructable, but you need to add a main image for the project!

Please do that, and reply to this comment so I know when you are done.

HammE2 years ago
Wow! Just gave me another thing to think about building!
What kind of clutch did you get and where did you get it?
florman2 years ago
Hey I want to make a racing mower and was wondering if you could take look at this mower i found for sale near me and tell me if you think it would be a good choice as a racing mower


Its a Wizard dont know the year
SimonK953 years ago
We are currently working on a 14.5hp engine, and we have fully stripped down the body and lightened it all, But we don't know hope we change the gearing on it? Any advice would be great, but make it sound simple, as this is our first build? Engine is an Intek so advice would be great?
Wesley6663 years ago
Current racing mower. It does not meet any of the American Racing Mower Associations rules and regulations, for any class because its a high power, 2 stroke from a snowmobile, as well, there is only one class I believe that allows the CVT clutch and transmission it has to be legal. Mostly wanted to make it for the hell of it, see how fast I can get this thing to go (I want it to for sure hit 120km/h, but that is really quite easy for the engine I am using).

Also, bought a different engine then I intended to use. I planned on using an 110hp Arctic Cat engine, but I am selling it and using this little 30hp 340 instead, seemed a little more reasonable. I want to lower this mower in the back, use wheels only slightly larger then the front instead of the big ones that came on it (Also because I am custom making the whole drivetrain, I can make it to whatever wheel size I want) and I want to keep all the body panels on, but adjust the main one so the seat sits lower.

The drivetrain that came off this has both a high speed 90 degree gear box which would be great for a lawnmower engine to get it driving a shaft horizontally, as well as a 4 speed w/ reverse transmission with differential. The transmission is bullet proof, solid cast iron construction. 1st gear has loads of power, if you punched the pedal you could get the front end of the tractor to come way up off the ground, 4th gear without mods would run this tractor up to about 50km/h. I would like to use the transmission in a go kart sometime with a manual clutch, I could make a mean racing machine with that setup.

Old lawn tractors are by far the best lawn tractors you can get, do a pulley swap and tune the engine, you could probably hand a lot of people their mowers on a silver platter with a near stock machine.
billybob64 years ago
whats the eaisiest way to reinforce the frame because i cant weld
also, the best way to learn to weld is to practice on scrap metal. under the mower don't have to look pretty as long as it holds. just remember, DON'T weld it all the way, stitch weld it so you don't warp the frame. i live in N.E. and we build mowers that can go 100 mph+
Sorry Pal, ain't no mower gone 100 mph yet.
I see nothing to indicate this "mower" reached 100 MPH and sustained that speed. Bobby Cleveland driver and racer, sponsored by and employed by Gold Eagle went to the Bonneville Salt Flats (twice) and still was unable to reach 100, but he was close. The video can be seen on the USLMRA website. My brother, Chuck Miller, was there as part of his pit crew for the attempt. Bobby's speed was documented by the Salt Flat organization. So a claim is only a claim unless you have bonafide documentation to back it up. Video of a machine running illegally on a public road doesn't cover it.
I just realized though, you probably have to use a stock engine that has been upgraded, not transplanting a monster of an engine into them, correct?
No one has gotten a lawnmower to do 160km/h? Seriously? I just picked up a 110hp sled engine from a 2004 Arctic Cat Sno Pro and was planning on putting it in a lawnmower to motor around on. If you can get a sports bike to hit 200km/h with less then that I think I can get a lawnmower to do 160km/h. Clearly, no one has really put in a good effort to get a lawnmower to go balls out. I think I could get a lawnmower up to 200km/h easy with 110hp.
i have found the best way to reinforce the frame is to use 3/4 square stock along the top corner of the frame. this will make the frame very strong but not add to much weight
i have looked all over for a ragb and can only find either reducers or 1:1 ratio boxs, but most are only rated for 2hp and at a costly $250. could you please give me the specs on your ragb and where you got it.
go on ec distributing. go on mower parts and the very right bottom link will say right angle gear box. or get a peerless 1100
go on heymow.comgo on peerless.com. find a p-91
i was wondering if i take the pulley from the back and connect it to the engine and the pulley on the engine to the back would it make it go faster
aswracer3 years ago
i have a old mtd with 6 speed stock i wanted to know how to make it work for speed?
go on hey mow.com. otherwise just take out the factory grease and reverse chain and add some realy good grease of gear lube
rabrantes3 years ago
Also where did you locate your fuel tank and how big is it?
rabrantes3 years ago
I really like the design of the frame you built and I am interested in building one during this winter. Could you tell me a couple basic measurements of the frame? How long and wide it is? How far from the front of the frame to where it becomes two frail rails? And the distance from the bottom of the bottom frame rail to the top of the top frail rail by the rear axle. I would appreciate it, thanks!
McClellan413 years ago
i was goin to do this to mine but never did and now wish i had!!! but might have to down the road!!
McClellan413 years ago
i have the same thing but not spring loaded its stationary and it has worked out great so far!!
McClellan413 years ago
so which ratio has a better acceleration (power) 6:1 or 2:1??
McClellan413 years ago
ya hi i was wonderin what size sprocket i should use on the input to the ragb..i have 17t on my clutch and the ragb is a 1:1 ratio???

chivesg56 years ago
I am using a ragb and balts what size poles should I use how fast would it go and from the ragb to the axle iam doing by chane what size sprocte shoul i use
mowerracer (author)  chivesg56 years ago
I'm not sure what you mean by Poles. As far as speed, it depends on your ratios. On mine , the clutch has a 14 tooth sprocket. From there it goes to a 14 tooth sprocket on the RAGB input. My RAGB is a 2:1, meaning 2 turns in, 1 turn out. The output on my RAGB is a 12 tooth sprocket and from there it goes to a 40 tooth rear axle sprocket which gives me around 35-40MPH on avg. Making the sprockets bigger or smaller will affect the speed. For example, putting a smaller rear sprocket on the axle, like a 35 tooth sprocket would increase the speed. Its hard to determine exactly what the speed will be. Most of us just make a rough approximation then fine-tune by adjusting. I already went to a smaller rear sprocket to slightly increase my speed. Just be aware that most sanctioned racing organizations have a limit on what the final ratio is. I believe 8:1 is typical, but double check with the USLMRA, or ARMA organizations first.

  Engine/clutch 14tooth -> 14tooth on RAGB=Same ratio.
  RAGB has 2:1 ratio. Now engine turns twice for axle turning once. RAGB has a 12tooth and rear axle has a 40tooth.
   40tooth / 12tooth = 3.33 ratio x 2 (from 2:1 ratio in RAGB) = 6.66:1 over all ratio.  
  Tires are 11 inches in diameter.
  With that ratio your speed will be:
5000RPM=24.56MPH and
  Changing ANY of the numbers changes the MPH. If you change to a 36tooth rear sprocket then the ratio becomes 36/12=3:1x2(RAGB)=6:1 total.
Then the speeds become:
5000RPM=27.27MPH and
  These are TRUE numbers, IF the clutch is locked up and not slipping. Using belts, there may be belt slippage, making your speed a little slower.
  With a 40/12 ratio, changing rear tire from 11 inch to 12 inch diameter changes speed at 6000 from 29.48MPH to 32.16MPH.
  It would be easy to put all of that into a spreadsheet to show speeds for every 1000RPM and what happens when changing sprocket ratios or tire sizes.
 I made a formula over 35 years ago to figure numbers like that out, the formula is:

Nice Instructable.

  Ken Chevy
080810 1316
OK, after looking at your build i see that you are using a chain instead of a belt. also you are using a cintrifical clutch. whats the deal??? the way we race is with a belt, double pulley clutch. the only chain we use is between the trans and rear axle. i was wondering what rules you are using?
mowerracer (author)  gschmidt-24 years ago
I built this mower under ARMA rules for the Pro-X class which means I can use a single cylinder engine and am not limited to using a geared transmission. As such I chose a right angle gear box and a centrifugal clutch because its a much simpler setup. I always found gearboxes to be a pain as there's more to go wrong.
OK, that makes sense. we only have one guy with an f/x mower. what state are you in? I'm stuck in N.E. and if your not a farmer or rancher there's nothing to do during the summer but race. right now I'm finishing up a mower that i hope will go 100mph.
mowerracer (author)  gschmidt-24 years ago
100MPH is probably not going to happen honestly. We have quite a few machines on our team that are running modified Briggs V-twins and even for them we're talking maybe 40MPH tops. During our races our average speed is usually around 30MPH. Trust me- that is going to feel very fast on a rough track without suspension!

Either way, good luck with your build.
You should check out Bobby Clevelands last run at the Bonneville Salt Flats. He didn't hit 100 MPH, which was the goal, but he got awfully close to it. He said it was a scary ride. The was a video on the USLMRA website. Bobby works for Gold Eagle and takes their truck to a lot of the USLMRA sanctioned races including the national championship race at Delaware, Ohio, sponsored in part by my brother, Chuck Miller. Chuck owns Miller Lawn & Power in Marion, Ohio and the USLMRA Hall of Fame is currently located in his showroom on East Center Street.
would this ratio apply to mine im running 4500 rpm with8to1 i dont know the tranny ratio yet
You say you have a box that is 8 to 1.   It has two shafts coming out of it. 

If you hook the engine driveshaft up to one of the shafts, the other shaft will either turn 8 times faster or 8 times slower than the engine is turning.

You will probably be using it to gear the engine speed DOWN, so divide the RPM number by the larger number, that will tell you how fast the output shaft will be turning then.

Input RPM = 4,500 / 8 = 562.5  RPM output speed.


122810 2127
sorry i wasnt really clear ive got pulleys that are 8 to 1 then they go into the transmission which is either going to be a 5 spd spicer or a 6 spd peerless from a poulan . im hoping on getting 45 to 55 out of it.

I can't read minds (yet - LOL) and can't see the parts you have in front of you.

So, you have to give me numbers.

Make a mark on the input shaft of the transmission and another mark on the output shaft.  Then put the transmission in 1st gear and count how many times the input shaft goes around to the output shafts ONE time.  If the 5 speed goes around 10 times to one time for the output shaft in 1st gear, then that is 10/1, and 7 times in 2nd gear it would be 7/1 etc.

You HAVE to have the numbers to figure out the ratios.

So you will HAVE to get both transmissions, mark the shafts and count the turns to get the ratio for each gear...OR that info (transmission ratios) may be available from a dealer. 

But you MUST have:

Engine RPM
Pulley ratios
Transmission ratios
Rearend ratio
and, last but not least the Tire Diameter.

Once you have those numbers, then input them into the formula I furnished:


If, for example, you have 4,500 Engine RPM/8=562.5 engine RPM
Rearend ratio of 6/1
Transmission ratio of 5/1
and a Tire Diameter of 12 inches

then we would do 4500/8=562.5
225/336.13524=.6694 MPH

Less than ONE MPH @ 4,500 RPM engine speed.

So, get rid of the 8/1 and make them 1/1 pulleys.
Then the MPH would be 5.355 MPH

Change the rearend ratio from 6/1 to 2/1 and then you have 16.065 MPH @ 4,500 RPM engine speed.

Then change the transmission ratio to 1.5/1 and your MPH would be:

53.5499 MPH @ 4,500 RPM's of engine speed with a 12 inch tire.

4,500 RPM engine speed (w/1/1 pulleys) + rearend ratio of 2/1 and transmission ratio of 1.5/1 with a 12 inch tire = 53 MPH

Put different numbers into the formula, John.  It will work every time.  It is simple, 2+2=4 every time.


I used to use that formula a lot when I was drag racing years ago. 

You can use a regular calculator, use the one in your computer works fine, and just do them one step at a time.    Try it, figure out some ratios, John.

And, like mowerracer said, 45 to 55 MPH is pretty improbable without having an engine putting out a LOT of horsepower!

And it would take so long to get up to speed too, because of lack of HP.

You might try it with a 3.5 rear ratio to start with and that will be about 30 MPH and see what that is like.


122910 1438
finally got the ratio from the tranny 6 turns of the shaft = one revolution of the tire the tire is a 12.5 . so i think i got the math rite but im not so good a math either motor 4000 8to 1 means 32000 on the input shaft of the tranny = 5333 of the tire in 5th gear rite ? for every 1 turn of the motor im getting 8 out of the in put shaft on the transmission .
thanks for the equation !
thanks just trying to get an idea of the speeds im attaining ill be putting a 18hp briggs twin on it once i race the twelve horse for awhile
mowerracer (author)  JOHNTHEREDNECK4 years ago
45 to 55MPH would be improbable with a mild modified build. The average speed that we attain in our group is roughly 27-33MPH and trust me- that feels FAST out there on the track. Just as a reminder, if you are building on of these you will need to adhere to the rules and regulations outlined by one of the sanctioned organizations like ARMA or USLMRA. These rules are created to make your ride safer.
im following the guide lines from NELMRA im going to run in the prepared class when ever i finish this project.
mowerracer (author)  Ken Chevy5 years ago
Thanks for the math Ken. As mentioned- my math skills are not exactly great.
there is a speed calculator for go karts, or anything really, if you go to http://www.diygokarts.com/
  No problem.  I put the math there so anyone, including you, can follow the steps and figure out your ratio's and MPH@RPM.

  If you change your axle sprocket to a 24 tooth, which would make it  2:1, then you could obtain 50MPH at 6,111RPM if you had enough power.

  It looks like it would be fun.

080910 0820
rebel91514 years ago
hey bro i goy a murray lown mower with the same size engine now if u didnt wanna buy parts but wanted to make it go faster what would u do
You can make it go faster just by taking off the gonvener and adding a throttle cable, But I dont suggest doing just that, there is a lot more to it. I have been racing for about 10years now and only have $200.00 in my mower at our local track, Top speed on it is 63mph but on the track we run the cops clocked us at 40mph in the corners and the best they could get was 57mph in the straights. I advise to strip the mower and start with the frame before you do anything, I have built 3 murrys but preferr the craftsman all modified and bought nothing but pulleys, belts, bicycle brake cables, and spark plugs just to get started
mowerracer (author)  WARDAWG944 years ago
Yes, its possible to go fast with a stock mower( or almost stock) But for the sake of safety I'm not going to recommend doing that. I've seen way too many stock front axles split and break, and too many accidents from stock component failures. A stock mower setup to go fast would never pass inspection at an ARMA or USLMRA event. Anyway, be safe and good luck.
DO you think it would be okay to do this, but not race it? I just want mine to go a little faster to get around. Im not going to race it on dirt tracks.....
mowerracer (author)  rebel91514 years ago
Hi there,
Its really not a good idea to run a riding mower as a race mower without modifications. That means a different modified steering system, "real" brakes- not the ones the mower came with- frame stiffening, and so on. The reason is because these mowers were designed to go no more than 3-4 MPH. I've seen a lot of people who have tried to race a stock mower and wound up having accidents. So in that case I would not recommend making your mower faster without making it to fit the rules of one of the sanctioned racing organizations.

Anyway, good luck!
Lawdawjr4 years ago
Is it a good idea to make a rear engine snapper a racing mower? i have one but before i get started i thought i should ask so i dont waste my time
HA on the step 19 pic i thought "y is he talking about his fence" :D
jmichels14 years ago
Hey,Mowerracer what would u think I shold do with a Kowasaki liquid-cooled V-Twin with about 17.5 hp, and how could i modify that.
mowerracer (author)  jmichels14 years ago
Liquid cooled engines aren't actually allowed in sanctioned mower races for various reasons. But something else to think about is that this is a sort of rough sport and we bang into each other a lot. The last thing you want is to smash a radiator out there.
cbartley4 years ago
so i have a a simplicity cavalier and i want to make the thing go fast with blowing it up, what do i do, and does using the govnor actualy blow up the motor?
sethypooh4 years ago
how much hp it has after the build
Used riding lawn movers are mainly meant for bigger lawns so that the cutting process should be done effectively and efficiently.
mowerracer (author)  willamalex8004 years ago
Yes- I would agree. Its just that some of us find it more entertaining to make them go faster.
gcarse4 years ago
I was wonder what type so steel the axel is made of because I am interesting of making on.
Can anyone help
mowerracer (author)  gcarse4 years ago
The steel used in the axle for mine is Chrome-moly steel. Its generally pretty cheap to just buy one from a got cart shop or online. These are actually hollow and have keyways milled in.
Hello its me again
Just another quick question
How is you Sprocket and Disk brake connected to your axel?
mowerracer (author)  gcarse4 years ago
No Problem. The way it works is that the axle has key ways cut into it. Before you put the wheels on you will slide your brakes and sprockets on. The brake disc is mounted to a hub. The sprocket has a hole that is sized for whatever sprocket you get. So let's say you got a 1 and a quarter axle. You would get a brake hub and sprocket with a 1 and a quarter inch bore. The sprocket will have set screws and a key way cut into it as will the brake hub. Then you buy keys that fit these which prevents them from spinning. The set screws tightens everything in place.

Hope that made sense.
codyMT884 years ago
Couple questions, I'm sure you've answered them in the past, but I have about two minutes a day to do computer haha...

1: What make/model is the RAGB? I'm having a hard time finding one that can take more than a couple thousand input RPM

2: Would 1" go cart axles/assemblies from Northern Tool be suitable for a reliable machine?
mowerracer (author)  codyMT884 years ago
Answers below:

1: The make or model isn't important. What you can look for are gear boxes for older mower decks or gear boxes for snow blowers. Mine is an International, but these are sort of difficult to find.

2: 1.25" is generally a better size because there's more parts and components that will fit it. Plus 1" tends to bend easier. Check online for go cart parts. That's where I got mine.
paullove4 years ago
the centrifugal clutch
where do I get 1 that is strong enough?
mowerracer (author)  paullove4 years ago
You'll want to use one rated high enough for 10-15HP. I used a Titan Clutch rated for 15HP. Another good brand is the Noram brand.
hellguy4 years ago
where can you buy this stuff from
bessner504 years ago
im makin one for goin muddin with my buddies and i need to get power how would you do that?
mowerracer (author)  bessner504 years ago
There's actually a site for making offroad mowers. These aren't made for speed per say, but more for climbing and not getting stuck. Check out this site:

For what you put onto one of these, you could probably pick up a used 4-wheeler that would be better suited to the application. Of course, then you miss out of the fun of building it.
mowerracer (author)  gordzooks4 years ago
Depends. Last time I looked a new 4-wheeler costs as much as $10,000-$12,000 and used ones for $2,500 and up. You could build something like one of these for under $1,500 and plus- its would be an off road mower which would give you more brownie points in regards to "coolness" in my opinion anyway. Besides- part of the point of this sport is the ridiculous aspect of making household riding mowers into racin' machines.
Don't get me wrong, I like the idea of lawn mower racing. It's just the idea of the off-road mowers that strikes me as more work than it's worth for the results. For the money you could pick up a used Samurai or Jimmy and torch the top off.
jeff0917964 years ago
would the front axle work on a sears lt 11/36, this is a huge riding mower, my steering linkage from the gear to the spindle broke, and they don't make it anymore, thanks jeff
mowerracer (author)  jeff0917964 years ago
It should work with that Sears mower just fine. The thing to remember is that the stock steering systems on these mowers are pretty much useless. The geared system you mentioned is notorious for breaking and slipping if used for anything other than mowing. The idea is to create what's known as a "direct" steering system. In other words- positive linkage from the steering wheel to the spindles. There are a number of front axle manufactures like Acme as well as some from a company called EX motorsports. They should have the neccesary hardware to enable you to make a direct steering system. Check out www.heymow.com and look at some of the project builds to get an idea of how to make your steering system work. There are some good ideas there.
If you just want it to go fast put a 6" pully on the front and a 3" on the back my old one toped out at 70 kph take the deck off and just weled the front so it dosent flop around if all you want to do is tour with it just do that it's fun

And if anyone knows What size of gear I should put on the trans the clutch is a 10 tooth should I just put a 10 tooth on?
mowerracer (author)  mitchell16114 years ago
Not trying to be smart, but as I mentioned at the start of the instructable I don't recommend people building these just for fun. If you do build one, do so using regulations and rules setup by either the USLMRA or ARMA. These mowers need to have a fully reinforced frame, an upgraded braking and steering system- which means getting rid of the stock crappy axles- a safety tether, and so on.

ARMA rules here:


Good luck.
what is the chain fer? and is that a cool air intake like on a car? sorry bout all the questions
i ain't really got that many places to go to race. i live in lawndale n.c. and the closest place to go is harris speedway. they have them every once in a while and my buddy raced a stock one. he said that they jus let em have at it. he was on a 21.5 hp and got beat by a 5hp snapper. that wuz funny. and is there another way to make poss traction without welding the rear end? cuz that'll screw up yur rear end after a while and if it breaks during a race yur screwed. thank yu and i know its not for fun.
howdy. uuuhhhh, i gots a question. i aint got no idear where to start building my lawn mower. i gave a murray with a 12.5 hp briggs and straton and a ( i fergit wat it is) mower with a 7 speed manual transmission. yu put er into gear tween yur legs and you shift the gears beside you. its 14 hp. i need help. is there any way i can supe it up without having to bore over the motor? i know to git a pully off the blade deck or buy a half inch pulley fer the rear end. sorry ter bug ya
mowerracer (author)  redneckracer4 years ago
A good place to start is to determine what organization you want to be a part of. There are 2 primary organizations in the US:
Both have chapters and clubs throughout the US and one will probably be near you. Both organizations have set rules and classes. You will need to build your mower to these specs in order to assure it is safe. There are a number of helpful web sites devoted to mower racing. Look up www.heymow.com and take a look at some of the mower builds in the build section. If you have questions, please feel free to ask.

The key here is to be safe. Read the rules for either USLMRA or ARMA and see what the specs and requirements are. Do so and you'll be in good shape.
Good luck.
Hey I have a 11 hp Briggs and I just bought a centrifugla clutch for100$ and it's a 14 tooth what should I put on the peerless 700 transmission (6 speed) ? Thanks Mitch
hei i have a question which transmission would be best a peerless 6spd out of a poulan or a 5spd spicer from a craftsmen ?
mowerracer (author)  JOHNTHEREDNECK4 years ago
Are the transmissions you mention hydrostatic? If so you cannot use those for higher speeds. They simply burn up. If its a conventional Peerless 5 or 6 speed box, then that would be fine but you will need to make sure and use a steel plate to mount it as well as a hole for the output shaft of the transmission to fit through. That will reinforce it because otherwise the output shaft will snap.
no theyre not hydrostatic theyre both gear drivin. put a steel plate around it on the top would angle iron work ?
why do i need a chain when i could use a driveshaft?
its a choice you could stick with stock or mod it up
Hey, Were did you get your magnesium piston and aluminum rod? Im working on my race mower for a shop class project, to race at the county fair. Thanks.
mowerracer (author)  dieselman20135 years ago
I got both of them from a small shop called EC distributors. Here's a link to their parts:
how would i put a fuel pump carb on my 12hp briggs i/c ? carb is off a 18hp briggs vtwin i blew up a few months ago :). where deos the vacum line go / what do i do with it. help please.
mowerracer (author)  JOHNTHEREDNECK4 years ago
The 12HP briggs didn't come with a fuel pump so there won't be a vacuum line for one. The best bet for an engine like this is to make sure your gas tank is elevated far enough above the engine to give you proper gravity.
could i run the vaccum line off the intake would it have enough vacum to do it ?
i know, i just want to know if it can be done because Ive got the set of skills to do what is necessary what is it just a plate with a hose fitting connected to the pcv?
hey i have a b-115 wheel horse lawn mower. if i want to swap out the pulleys, where would i get the parts for that. thanks
rilley13134 years ago
hey where do you get all of your part/components
mowerracer (author)  rilley13134 years ago
The steering components came from Acme Mowersports ( look them up online) , EC distributing, and Ebay. A great many components are actually go-cart parts.
rilley13134 years ago
hey where do i find this right angle gear box?
mowerracer (author)  rilley13134 years ago
I found mine on Ebay. That's generally been the best place I've been able to find older parts.
vladn84 years ago
im trying to make one just to have fun on how much would i have to modify it to go fast?
mowerracer (author)  vladn84 years ago
As a member of ARMA I can't really recommend you make one of these just for fun. The primary reason is safety. If you build one to one of the specs setup by one of the sanctioned bodies, you'll have a safer machine. These are only meant to be raced at approved tracks and facilities. Trust me on this one- I've had my share of wrecks on these and having an accident at 30-40MPH could and on occasion do cause serious injuries. So please play it safe and if you are going to build one, please visit www.heymow.com and lookup a racing chapter in your area. We are always happy to help new racers but we also want everyone to be safe.
No hard feelings.
jordangamm4 years ago
So how did you get your exhaust off? If I'm seeing correct your exhaust looks to have an extension to the old muffler, mine doesn't would you have any idea how to get it off? Thanks.
mowerracer (author)  jordangamm4 years ago
Its hard to see how yours is held on in the pic. There's two ways these mufflers are mounted. One way is that they're simply screwed-in. The other way is that there will be two bolts holding it on. If you see no bolts, try twisting the muffler counter-clockwise ( left) and see if it will unscrew from the exhaust port.

The muffler on mine was fabricated from a combination of a muffler pipe from a Snapper riding mower and a length of pipe I bought from a muffler shop. The trick is to get the right bend in it so it will fit the frame, which is generally why the exhaust is done last after the frame, steering and braking system has been modified.
jordangamm4 years ago
How did you take the old air filter off and put the pod filter on? Thanks.
mowerracer (author)  jordangamm4 years ago
I bought an adaptor for the intake side of the carb. You can buy these from EC Distributing. Here's an example link:


This will enable you to fit a K&N motorbike style filter as seen on mine. The part is pretty cheap.
Would this suit a 12.5HP Briggs and Stratton motor... I want to put a pod filter on it. Also the rubber warming pipe that comes out of the motor that was connected to the old air filter what happens with that? Thanks.
mowerracer (author)  jordangamm4 years ago
Yes, and in fact the engine I'm using is the same engine you have- a 12.5 briggs flathead. All of the previous air filter components don't get used. You will basically just have the new K&N filter and that's that.
OK cool, So can you send me the link to the part that will fit mine? Thanks.
mowerracer (author)  jordangamm4 years ago
If you look at my response above there is a link to that particular part. BUT- give them a call BEFORE your order. Tell them what engine and carburetor you have. That way you'll have the correct part.
OK Thanks for that.
harden up4 years ago
how much would it cost all together to make one
mowerracer (author)  harden up4 years ago
It depends on a number of factors: What class you're racing, what parts you already have on hand, whether or not you have a mower handy, and what quality of components you use. For example there is a stock class which means you pretty much have to go stock speed.

As for this mower, we're talking probably around $1,500 realistically. That's actually a lower end number as I was able to buy a lot of used parts like the aluminum flywheel. My first mower which was far less modified was around $600.

I look at it this way: A typical go-cart is going to set you back $10,000 and you will probably have to change the tires for every race- or $200 in tired per race. Mower racing is about the cheapest motorsport around.
ryanhare924 years ago
Ive been running a belt drive with my transmission and have noticed cracks are starting to appear all over my belt. What is the likely cause of all these cracks forming?
turbofuzz4 years ago
I have a briggs 16hp vangard with a cast iron bore... i have never done anythaing like this so i have no idea were to start... first is this a good engine to work with? and what is the first place i should start..... you can send me an email at brianbsadams@aol.com... with any websights or list of thaings i need to do... thank you
What kind of speeds are we talking here?
mowerracer (author)  SonOfaVermonter4 years ago
We actually clocked ourselves last year. Our average speed was around 27MPH. Since then we might be going a tad faster because we keep upgrading our machines. I plan on overhauling mine ( the machine featured here) this winter. One of our team members attended an event in TN last fall. Some of the mowers were approaching 50+MPH. That's a little scary!
That depends on the engine, gearing, and weight of the whole thing. I know a common range of speeds are anywhere from 20-40 mph on your everyday engines.
mud-dawg964 years ago
does anyone know what the max RPM on a craflsman 11 hp engine is
factory setting ? if its a briggs they run 3600 rpm stock i would without racing parts i would only push it to 4000 or 4500 because of the flywheel if its not a cast iron bore just put it aside and buy a 16 or 18 hp v twin or single just stick to cast iron bore the last longer and run better motors come cheap if you look around.
Probably around 3500 RPMs. Look up your engine online and see if you can find the specs. Most horizontal engines are governed for 3500 RPMs so I could see most others being that. My 3.5 Briggs only goes 3500 too.
im having trouble finding an old mower like the one you used. and ideas on where to get 1, or whats the size of your mower? if i knew the size of the frame i could just custom make a frame. help please? thanks
mowerracer (author)  arthurkaylee5 years ago
Mine is really tiny. The frame is only about 40" long and 20" wide ( measuring the interior box frame). These mowers tend to be hard to find on the West Coast for some reason. If you live in the Northeast or Midwest, it seems that there are tons of them around there. Look on Ebay. There's always a few floating around. Look for the brands: Huffy, Mustang, Rugg, and Grants.
Wheel Horse made some smaller mowers back in the day too

Could that be because a lot of them were snow blowers?  That may be the reason there are so many of them back East and in the Mid-West.

Thus they turn up on eBay.  A fun sport and lots of hours of fun for a couple thousand dollars. 

Some readers seem to think they are going to remove the governor from their lawnmowers engine and go have fun.  That is not going to happen.  When you show up at the race track, even if it is just the County Fair, they WILL have tech people there and your race-mower MUST have all the SAFETY mods and pass them.

082410 1505

mowerracer (author)  Ken Chevy4 years ago
Could also be because the grass just stops growing out this way around May. Its not as common for people to even own riding mowers out here- also because the cost of real estate is sky-high here and hardly anyone can actually afford a lawn large enough to need a riding mower. Back where I'm from in the South though... you HAVE to have one since the grass grows like mad.
hi i have a 1972 craftsman and i want to make it a racing tractor you see i ported the cylinder and jetted my carborator in my dirt bike can i do that to my tractor?
The rule book for ARMA - American Racing Mower Association, is in .doc format:  16 pages.

2010 ARMA Rules - .doc file. Click here:

Notice what USLMRA says about WHAT a racing mower HAS to be:

Home > Rules & Tech > Offical Rules - The following link is for ALL their rules.  You can either RIGHT CLICK on it and Choose Save As or just click on it and it should open in your browser window.  34 pages.

Download the Official USLMRA Rules: Click Here:

Cool, put the blade back on your racing-mower and cut your lawn!

082410 1552

yes you can but if your going to go theat far whith the carb and pull the govenore get a mikuni carb that will fit your motors needs
ryanhare925 years ago
I am a teenager and am wanting to get into lawnmower racing. I want to use my v-belt setup that I currently have. Right now it has a tension drive clutch but I was wondering if I could get rid of that and use a centrifugal clutch. Does the Centrifugal clutch go on the drive shaft of the motor? Also, does it basically just stop spinning when the RPM's are down, is that how it works? Thanks, Ryan
mowerracer (author)  ryanhare925 years ago
Hi Ryan, First of all, if you plan on racing in a group like ARMA or USLMRA, you have to be 16 or older, so just keep that in mind. Doesn't mean you can't build a mower, but I just wanted you to be aware of that. Anyhow, You can use a centrifugal clutch but keep in mind that the clutches you would need to a larger engine are kind of pricey, as in $160-$200. You need to make sure that the clutch is for a 1" bore. The clutch goes on the drive shaft on the motor. How it works is that there are 3 metal "shoes" inside the clutch that are attached to heavy springs. Once it spins fast enough, the inertia will cause the shoes to contact the clutch surface. Usually it will engage between 3000 to 5000 RPM. I usually run at 3000 RPM because it gives you more control. They come with 3 sets of springs. They are color coded and each color is rated for a faster and lower speed. So you can change them out for whatever speed you want to engage at. Lastly, most of these clutches come with a chain sprocket, but if you know how to weld or know someone who does, you can use a tig welder to weld a belt pulley to it. Its not super hard. I just ran chain on mine because with a chain, there's no belts to wear out. So you might look into a chain setup. That way you could avoid having to weld a pulley to the clutch. The other option is to use the belt clutch, which most people usually do. If you have it setup just right, a belt will last a long time. There are only 2 guys running chain in our group. Me, and another person with a similar mower. The rest use belts and some of them are going on 2-3 years old. So a belt isn't a bad option. The centrifugal clutch is just more convenient because you can avoid having a foot pedal for the clutch and just punch the gas and go. Good luck and if you need any more help, let me know!

And I believe USLMRA says MAXIMUM engine RPM's is 3,650RPM.
Hey man i got a lawn mower of my cousin i was just wondering if u could change the lawn mower so u could have a foot petal instead of the shifter and is it possible so u can tack rpms up with the foot petal then when u get to a certain point have it kick in gear get back to me thanks
im am just now building one  with a i/c 17 horse engine with a dynamark lawn mower body with out the blade deck
if your motor is a vertical shaft and stock tranny i would use the belt (its easier to do wheeles) its not hard to do any of this im only 17 if it wasnt for mowerracer i wouldnt know as much as ive learned now, what ever you do have a blast and enjoy it.
mowerracer (author)  JOHNTHEREDNECK5 years ago
John, Just a heads-up, but if you're modifying a mower you need to make sure that you are being safe with it. I would highly recommend joining a sanctioned organization like USLMRA or ARMA. They will have rules and regulations that are specifically made to encourage safety. Bottom line: These things aren't really meant for wheelies. In regards to a centrifugal clutch, if you get one its best to buy a good quality rebuild-able unit. I have been running a Titan clutch rated for 15 HP and so far its lasted 3 years. The shoes are cheap and easy to replace but so far I haven't had to do that.
ok thanks i just dont know if there are any organizations in rhode island thanks i will look for them i was thinking more of county fairs and see where i would get from there
you can use centrificul cluches they are awseom but they wear just liken anything over time mowerracer is right thow its easyn to have no pedals to use as a clutch. belts last a good amount of time is your motor a vertical or horixontal shaft
Mine is a vertical shaft. I ended up going with the belt and clutch setup because that seemed to be the easiest and cheapest. It seems to work pretty well.
luvit5 years ago
this should halp you mow your yard before the next rain.. if your a procrastinator.
Ken Chevy5 years ago
  Hi, In Step 3 you say:
  "Generally, it is better to have the left wheel turn in more than the left."
  Should the last word be 'right'?

  Nice Instructable.

  Ken Chevy

080810 1320
mowerracer (author)  Ken Chevy5 years ago
Yes... Sorry about the typo.
  I guess I missed something or don't understand something about instructables.  I have never made an instructable, but are you saying a person can NOT go in and correct errors?

   I would have thought the owner of the instructable could correct errors? 
  A person should always correct errors if possible so people reading the instructable  doesn't get frustrated because they can't figure something out because something was entered wrong.  You correct your mistakes so people understand what you have written.

  Like I said above, you have a nice instructable, well written.



080910 0829 
mossimo36 years ago
Is it at all possible to make the mower run fast by still using only stock parts? At this point I'm not looking to make it an extreme racing mower, just something fun to ride around in that goes somewhat fast. Also: Would a 1/4 inch steel plate be sufficient in preventing harm if the flywheel explodes?
mowerracer (author)  mossimo36 years ago
The short answer is yes, but I wouldn't consider doing it. The reason is simply because the brakes, steering , frame, and the rest of the mower is built to go 3-5MPH max. The stock spindles on these mowers have a tendency to split down the middle if put under lots of stress. I know because we had a guy who raced with a "semi-stock" mower using the stock spindles. The mower flipped over because the right spindle cracked in half. That can be really nasty if you're going fast. That and the brakes these come with are useless at high speeds. As far as the flywheel, some protection is better than nothing, but there is a tremendous amount of energy released when one of those suckers explodes, and a 1/4" thick steel might/ might not stop the shrapnel. I will say that so far, I'm the only guy in my club with a billet flywheel yet none of the guys running stock wheels have had one blow up. But that doesn't necessarily mean they won't either. Anyhow, you can get away with making a lower cost racing mower using go-cart components. Check out www.heymow.com and read some of the builds to find one that fits your budget. Good luck!
No way it's getting through 1/4" steel, BUT the mounting of that steel to support members, bolts or welding/etc is the weak point. Bits of metal may still fly out somewhere around the plate at high velocity.
mowerracer (author)  ac-dc5 years ago
Precisely. The bottom line is that no flywheel is entirely safe. There is always the possibility that a flywheel can explode- even the billet ones even though the chance for them is much lower. The problem with a scatter shield is that the only place to mount it is the engine and the engine being made of cast aluminum is not going to withstand the force of a exploding flywheel.
If anyone is interested in a fun lawn mower race, there is one at the Morton Logger's Jubilee held on the second weekend in August in Morton, WA. Suzanne in Orting, WA
waynecreech5 years ago
The bleeder fittings should be on the top not the bottom of the caliper...
What is actually left of the 'host' lawn mower?
i have a 14.5 hp briggs and stratton 7speed and i was wondering if i took the governor off if it would go faster or one of my friends said that it wouldnt go any faster because it was geared so low in the transmission and the same in the rear end
Yes if it is governed conservatively, by removing that and increasing engine RPM it will go faster - and stress the engine more. However, since the (mower?) was designed within an RPM band where the engine needed produce more torque to drive the deck too, without that it only makes sense to go with a higher geared transmission also, it is a more important change than governor increase or removal.
zach13205 years ago
ok so when u made da gas pedal. u completly removed the throtal thing on the side of the motor, dose this affect the timming?
no it does not what your talkin about is the govenor and you half to take it out internaly to
no it does not dont worry about it
the piper5 years ago
not 100 % sure but i think your gears work out to be about 1.5? turns of the axle to 1 of the engine. just off my head so :S
I have a 12 hp briggs and stratton that the repair guy I took it to  (in the mower)  and he said the valve was burnedd out. (I didn't see the muffler was just rattling round on nothing)   It ran but like hell ,is  this worth rebuilding? and would it be hard for a novice? 
i have a manual if you need it no one bought it yet its still in the plastic and its for your motor to
but like moweracer is right if the blocks messed up you can fix it but it can cost you some money \
its not hard as long as you have common sense and a decent tool set you be fine just get a manual
mowerracer (author)  Rahdzhillaxxx5 years ago
Kind of depends on what kind of damage was done to the block. If the valve seat is either burned out or loose you'd have to have a new one pressed into place which can be pricey. If the valve is just burnt those are cheap enough. With mower repair its more about the labor because parts are generally cheap.

 The thing is that these 12Hp Briggs engines are dirt-cheap. I bought mine for $50 and I have a few people have just given me. They're super-easy to work on too. Go get a shop manual, a clunker engine, take it all apart and put it back together again. In fact, most lawnmower engines are pretty much structurally the same. A crappy little Briggs 3.5 HP engine will give you a good idea how these are put together.
 Thanks for the input I will get right to searching Amazon for some manuals (first thing I dont ever do is read the instructions on anything and it is usually the last thing I do and then it works LOL)  And I agree about the labor, If you cant do something yourself nowadays your S.O.L. be it cars, mowers, dryers, anything.  Knowledge is power after all.
xmichaelx5 years ago
 I have a 11hp briggs motor on the lawn motor im turning into a racing lawn mower.  How do i locate the govener and take it off or even modify it to get more speed.
hey if the model number is 252707 youve got the same motor as me the govenore is on the left rear of the motor if you take it apart i recomend you take it out internally and also if you do this run strait 40 wheight in it because its running at twice its normal speed so its going to break down and make the oil bubble losing viscosity and seriously screwing up your motor if you need it i have a 1981 service manual for it i they usaly run 45 and up but you can have it for twenty if you take the motor apart when you get it off flipp it over and then un bolt the oil pan it wont come of easy so dont force it use two screw drivers and get a corner and you should be able to get it off ill try to send you pictures of what the govenore looks like its easy to pull out its basically layin on top of the cam oh and note to self do not pull the camshaft out they suck getting it back together message me for more info
Bosun Rick5 years ago
As to the issue of belt/chain tensioners, did you consider using a belt tensioner from a car engine? they can be mounted with a minimum of effort, and if you pick one that allows it, the roller might be replaced with the skateboard wheel. Your opinion/comment?
mowerracer (author)  Bosun Rick5 years ago
Actually, I've since changed the tensioner for the rear chain. If you look at the last step, I show what I did to improve the original skateboard wheel idea. The tensioner for the clutch to the RAGB has been reliable. The belt tensioner from a car is a good idea though.
yester day i found out that the stock pcv relasa pressure as the piston coms down and shuts to let pressure build up when the piston is going to TDC if i take this off and modify it so thatn it lets out all the pressure in the crank caes on the down stroke wouldnt it give me more power due to less air friction
mowerracer (author)  JOHNTHEREDNECK5 years ago
In general if you're running the engine faster than factory spec you'll need to allow the crank case to breathe easier, which is why you will get more power.
ok thanks thats what i was thinking but i wasnt sure if it would have ill afect on the motor in the long run thanks.
knuckel5 years ago
 can you make a steampunk one? that would be auwsom! check my group for ideas ! www.instructables.com/group/steampunkfaces/
mowerracer (author)  knuckel5 years ago
Well... While it would be pretty cool to make a steam-powered racing mower, we tend to wreck these mowers frequently so if- say someone ran into the boiler that would probably do some major damage. I like the idea though. Thanks!
duh-man5 years ago
i have a lawn boy, 12 hp. oooohhhh yeah cool-aid!
worleyll5 years ago
 Racing mowers are awesome. I got an old 1986 Dynamark with an 11hp Briggs ran by belt to a 3 speed gearbox, then chain to axle. It goes at least 45. last night i also welded the spider gears in axle to make it  positive traction and it handles a lot better!
holty215 years ago
Hey man that mower is sick as!!!! now is there must welding neeeded? could you get away with no welding at all , as i do not have a welder??? also i dont really wanna make a racing mower all i wanna do is get a stock mower and make it go about 30kms what mods will i need to make this happen? and im tight on cash
holty215 years ago
Hey man that mower is sick as!!!! now is there must welding neeeded? could you get away with no welding at all , as i do not have a welder???
TSC5 years ago
How much did this cost you? good instructable!!!
Wicked dow5 years ago
This is the nicest racing mower ive ever seen
redzz025 years ago
hey i was wondering if you could measure the lenght width and hieght of your mower and the hoods length width and height please and thanks i wanna make a racing mower out of a mini mower like you but i cant find one anywere so i need to make a hood and everything from scratch
I have a mower like his, its in good condition id get rid of it for 15 bucks I dont want it anymore
mowerracer (author)  redzz025 years ago
I'll measure it tonight. But one thing to keep in mind is that many organizations require you to use an actual factory hood. So you might want to find a hood from another mower if possible.
miketryiu5 years ago
 wow wheels... how to you have wheels new? 
mowerracer (author)  miketryiu5 years ago
They're actually go-cart wheels, so yep- they're new.
dumpy16 years ago
do u really need to make the dogbone? i realize that if it breaks my engines done but do they break often?
mowerracer (author)  dumpy16 years ago
Hard to say. I didn't make mine. I bought it for $20, so it isn't a huge investment. Its more of a safety issue because with the engine that close, if the weights smash through the back of the engine, you'll have nice chunks of engine casing flying towards you. Secondly, that will basically be the end of the engine. I've blown a few engines. All of them blew because the stock piston rods are crap and snap in half easily. But after I got a new billet rod, billet dogbone, and billet flywheel, the engine has worked great.
mowerracer (author)  JOHNTHEREDNECK5 years ago
You might try Ebay. Unfortunately there just aren't that many out there so yes- they're kind of expensive.
me i have a 11hp b&s 4 stroke and im painting it and all so i want to build the motor right  thanks again
thanks im trying to finishmy tractor soon so ive got to hunt down parts for it
is that a special order to get that or what?
mowerracer (author)  dumpy16 years ago
Yes, and it is from ARC racing. Go to this site: http://www.g-team.us/ARC.htm
If he doesn't have any there, email him and tell him what engine you have.
how much did it cost you .
ryanhare925 years ago
Where did you get your tether switch from? I am looking for where to get mine from.
mowerracer (author)  ryanhare925 years ago
I got mine on Ebay. Look for safety switches for snowmobiles. You can usually get them for $10-$15. Get the ones that have the forks that pull out from the switch versus the rubber cap thing. Those dry rot.
ryanhare925 years ago
Do you still have the choke hooked up somehow?
mowerracer (author)  ryanhare925 years ago
Yes, I have a simple choke and I control it from the dash.
ryanhare925 years ago
Could you combine a centrifugal clutch with a multi-speed transmission instead of using a right angle gearbox? I was considering using my stock peerless 5 speed and I was just going to leave it in 5th gear with the centrifugal clutch. Think that would work? Also I noticed your sprocket on the clutch was kind of small and the one on your shaft was kind of large. I know with a pulley I have a larger one on my engine and then a small one on my transmission to produce a greater speed. How are your speeds with your setup and how does it work? Thanks
mowerracer (author)  ryanhare925 years ago
The short answer is yes you can run a centrifugal clutch to a 5 speed gearbox, but I've heard centrifugal clutches are a bit rough on gearboxes. I have a tiny gear on my gearbox output and a large axle due to general gearing. I basically have no gears for the transmission thus the output had to be tiny and the axle sprocket is actually quite small too. Most are around 45-50 teeth on the rear. Mine is only 28. My mower is sufficiently fast. Realistically probably between 28-35 MPH on the track.
ihcubcadet5 years ago
Hi, I am building a racer from a 88 ariens yt 11-38, I am using a 11 hp briggs at 3600rpm to start, I am planing on running a 1:1 ratio from the engine to a peerless model 745B, 5speed tranny, my 5th gear is 2:1, I than will have 8tooth sprockes on the tranny going to maby a 40tooth sprockets on the axil.
I was woundering with your set up about how fast do you go? And what is your rear tire size.
I am shooting for around 30-40mph in 5th gear.
Any help would be great, thanks,
mowerracer (author)  ihcubcadet5 years ago
My mower will go around 30-35MPH max. On the track,  30MPH feels like 60MPH. I'd reccomend you use maybe a 12 tooth transmission sprocket and a 30-35 sprocket on the axle because 8 teeth might be too tight for chain. Lastly, just as a reminder that if you're going to race, make sure you improve the brakes, steering, and reinforce the frame because the stock stuff these mowers comes with is totally inadequate for higher speeds.
Thanks. I have two peerless tranys, one has the fine spline and one has the corse spline, do you have any idea where I could find a 12tooth sprocket that would fit either one of those?
mowerracer (author)  ihcubcadet5 years ago
I would try Mcmaster carr.  http://www.mcmaster.com/#
 I'm having a hard time finding a right angle gear box that can support the RPM. The max I have seen is 2000 RPM. I want to use a 1:1 gear box if possible. 
mowerracer (author)  MadMechanicMike5 years ago
We usually use old mower deck gear boxes. Mine is off of a Cub Cadet snow blower attachment. Some of these were never really rated for higher RPM, but so far we've had no issues with them breaking. Just make sure to keep them full of grease and check them out every couple of races.
how long of an axle did you use?
mowerracer (author)  Brett.Harkness5 years ago
I used a 42" axle. You can adjust the wheels in or out to meet the max width requirement.
bobzzz5 years ago

can u use a Murry12hp lawn mower

brodewald105 years ago
do you think that a 1:1 ratio gearbox would work good. Not sure if it will produce enough speed. Or should i look for a 2:1 . I found one that is 1:1 and is preety good and will get it if i know it will work good with the speed
brodewald105 years ago
Where did you get your centrifugal clutch?
mowerracer (author)  brodewald105 years ago
I got mine off of Ebay. They cost around $140. make sure you specify for a 1" shaft.
What are those right angled gearboxes called ? and im in the UK. id like to buy one of those brand new. any ideas ?
scooter6675 years ago
What piece is needed or what is the trick to connecting a vertical shaft engine to a horizonal live axle.
mowerracer (author)  scooter6675 years ago
About halfway through the post I show how to do it. What I did was have a right angle gear box where a chain runs from the centrifugal clutch ( engine shaft) to the gear box. That inverts the chain to run to the rear axle. Other people use a lawn mower 5 speed gear box, most commonly a Peerless 500 or 700. Both of these are pretty common.
tj boyd5 years ago
where can i find a front axle for my new racing mower.
mowerracer (author)  tj boyd5 years ago
Amce Mowersports makes a full front axle, http://acmemowersports.com/
You can also make your own, which you can do using go cart spindles and steel stock.
i appreciate the information
maer355 years ago
where did you get the right angle gearbox
mowerracer (author)  maer355 years ago
Mine came off Ebay.
Merkatroyd5 years ago
how do you hook up the gas lever? I ordered one from acmemowersports.com, and it came with a nylon sleeve and wire, with round bits on the ends of the wire, and a small piece of wire with an angle in the end for hooking up to the carburetor. how on earth do these pieces go together? hope I explained it right.
mowerracer (author)  Merkatroyd5 years ago
Ya, it can be a little confusing, but if you look at the 5th picture to the right on this page you'll see how I did it. Basically you want to make the throttle on the carb spring loaded so that the spring will pull the lever and throttle back. If you look on the throttle on the carb it is a sort of lobe with 2 to 3 holes on the end. If you look on the front of the engine blower housing in my picture you'll see a piece of aluminum. That's a bracket I bolted to the side. I drilled a hole in the bracket for the spring. The spring then runs to one of the holes on the carb throttle lobe. You should attach it in a way that gives a fair amount of tension. Now if you look to the right side of the engine blower housing you'll see another bracket. I used a brass fitting that was small enough to let the cable but not the cable sleeve slide through. I went to the hardware store, brought the cable with me and found the right fitting, which you can see in the pic. Then you run the cable through one of the other holes in the throttle next to the spring. Use the little brass pieces that came with your kit to clamp the end of the cable. You'll want to adjust the clamp so that when you squeeze the brake lever the force of the spring will pull it back. Hopefully that made sense. I have used this setup for 2 years and it has been very reliable.
Thank you.
Hi, What the drive shaft diamter on your Centriugal clutch? like is it a 3/4 bore? Thanks Confused.
Thank you. Not so Confused now.
mowerracer (author)  dieselman20135 years ago
Its a 1" shaft so if you got a clutch, you would want to specify for a 1" shaft. But they come for 3/4" shafts as well. Almost all riding mower engines are 1" though.
hockeyteen65 years ago
I have a true test riding lawn mower and I need to know how to transfer the power from the cutter to the wheels. thank you.
mowerracer (author)  hockeyteen65 years ago
Well on most riding mowers there is a single engine pulley with two belts- one for the deck and the other for the transmission. The mower deck will have nothing to do with getting power to the wheels at all. power will come from the transmission. Lastly, just because this needs to be clear, the mower blades must be removed if the mower is going to be used to go faster than stock.
thank you
where can i get an engine like this for racing
Merkatroyd5 years ago
Thanks for going through the trouble to make this detailed tutorial. I've been building my lawmower for a while now, a year, occasionally taking breaks from working on it, so It was alot slower than your build. but it was very fun! my mower is an old craftsman mower, which is bigger and heavier than your mower (so yours can probly whip mine lol) but it's almost finished. I just need to find somewhere to mount the battery, and hook up the throttle. It's going to be fun. oh, and uh, by the way, I have a few questions: How big of an advantage do 12 horsepower engines with overhead valves have over flatheads? I have an engine just like yours, except it's a tecumseh, and has overhead valves. I THINK they breath better, and therefore rev higher. I know they do for cars. Would it be a good idea if I took an 18 horsepower engine and swapped it? If I have a centrifugal clutch which is rated at a maximum of 12 hp, would it last if I used it on the 18 hp motor? plus, I have some questionable parts. I have one pulley which has a big chip off of one edge next to the belt. would It damage the belt? I got a RAGB just like yours. I took the little sheetmetal cover on the side off, and one of the gears are missing a tooth!! would this fatigue the gears? do I need to take it out and replace it? what would be a good source for pulleys? I didn't use chains like you. and I can't seem to find a pulley more than 5" wide. well, thanks again, I hope my questions didn't sound long-winded, amateurish, or confusing.
mowerracer (author)  Merkatroyd5 years ago
You can do just fine with a smaller engine. There's one guy I know of on our forum who races with 5HP go-cart engines and he beats guys with much larger engines. The trick is spending some time getting the right parts and the right setup. I can spin my flathead much faster due to the performance rod, piston, and flywheel. The flywheel is much lighter, thus much better torque. As far as pulleys, well yes you could possibly damage the belt with it. I look on Mcmaster car and a site called cheapmowerparts.com for pulleys. They're usually not too much money. Go for steel or cast iron since aluminum pulleys will split due to the pressure and heat. As far as the RAGB... I suppose you could just go until it blows. Its hard to tell what will happen. Its generally not a good idea to go with a cracked gear. I guess what you'll need to consider is what would happen if it did blow, which is would it cause the mower to stall out suddenly, which could throw you off. Just be careful. As far as the clutch, 18HP might be pushing it a bit. Mine is rated for 10 HP and I'm using it on a 12HP engine and it seems to do fine. But 12-18HP might be... pushing it. You could try it and if you smell burning, then its time to consider another clutch. good luck!
how many teeth are on the trani sproket?
mowerracer (author)  juggalo4life5 years ago
There are 14 on the input and 12 on the output.
thank you, i have a 1971 broad lawn that im making racing, how many teeth are needed on the clutch
joecrap6 years ago
Why was Orange not a good Color? I was going to go with Yellow, or some other "bright" color.
mowerracer (author)  joecrap6 years ago
Nothing wrong with orange, I just wanted to do something different this year. Luckily, you can paint your mower whatever color you want and its legal.
hay man wat kind of mower do u have an do u no were i can get one from
mowerracer (author)  tj17965 years ago
The mower was a Grants, but the company went out of business a long time ago. You can generally use just about any mower. This instructable just gives you some ideas on how to modify mowers for racing.
Corky H.5 years ago
I am looking for some B&S High Performance Parts, For a 14Hp Flat head motor, in CT. It was my every day mower, to cut 4 acres. 1 day and took it to a friends house for the 3 annal pig roast, lawn tractor race ( obstacles, jumps and up a big hill) and that was a T-T TRAIL,I did take first place in the two tracks in different years. THE 12TH ANUAL party, ran four races. The fifth I lost Left cylinder. These boy`s our into building motor now. ? "BACK YARD RACING"
mowerracer (author)  Corky H.5 years ago
You can get high performance pistons, cams, rods, and other stuff for briggs engines on a few sites. Look up EC distributing as well as G-team racing. They both sell high performance parts for these engines.
Hellchild5 years ago
now imagine if you sprayed it, that would be sick
I am a female who is trying to do this is there any advice you have for me since I have no idea what to do?
mowerracer (author)  lmstandridge6 years ago
Well, we actually have a number of women racing with us in our group and its becoming popular with husband/wife teams. My advice is the same for everyone else: do a lot of research, see what you need to to in order to build one( such as reading this instructable) and if you have questions, let people like me know. Visit www.heymow.com and read through some of the build sections. The guys on there are always happy to help. Best of luck!
So where did you get your right angle gearbox. All of the gearboxes that i found are only rated to a HP of 2.
mowerracer (author)  corrysoccer166 years ago
The gearbox is out of a snow blower attachment for an International Harvester tractor. I found mine on Ebay. You can also use gearboxes that were used for mower decks on older riding mowers. These are made out of hardened steel and will take quite a large amount of torque. We have 3 guys in our group using them and so far none have had any issues in 2 years.
jjhoff6 years ago
now that I see how to build a mower how do I get a race track started in my part of the world?????
mowerracer (author)  jjhoff6 years ago
The easiest thing to do is look for a racing mower organization in your area. There are 2 major racing organizations: ARMA and USLMRA. These are US organizations. If you're in the UK, there's the BLMRA, which is the world's largest. I know there are others in Denmark and France. In any regards, these will have tracks pre-made with racing dates and so on.
menace2696 years ago
Do you have any info as to where the traks are located? Or can you point me in the right direction to locate them.
mowerracer (author)  menace2696 years ago
We are located in Potter Valley, CA, which is outside of Ukiah. You can visit our site for dates and directions: http://www.pvmowerracing.com
I have a murray 14 horsepower riding lawnmower and really want to get some serious speed out of it and I have no idea what parts and pieces I need to make it fast. iv already taken the mowing deck of and I need to know where to go from there. if you can help me plz do so. thx, walker
mowerracer (author)  racerofmowers6 years ago
Hi Walker,
You will need to upgrade the steering, brakes, frame as well as making changes to lower the overall machine. The stock components won't hold up at any speed over the stock speed the mower was built for. If you want to get some ideas as to what you'll need, read through the steps of this post as well as the builds on this site: http://www.heymow.com . It will give you some good ideas.

The way to look at it is that when you're done, the mower will be more like a go-cart rather than a mower.
difflock6 years ago
Does anyone know where I can get a new gearbox sprocket? I think it is a Peerless box (not sure on model, cant find a code :S) The one fitted is stripped, and cant find a replacement!
I am in the UK, so uk suppliers would be best...
mowerracer (author)  difflock6 years ago
I find that Ebay is about the best place for getting mower parts. The Gearbox you have is likely a Peerless 700, which are very common transmissions made by Tecumseh.
I couldnt find a plate or marking on the geabox saying what it is :S... I am going to take it out of the mower though, and check it over... If anyone can narrow the models down to my gearbox that would be brilliant. It is a 5 speed forward, 1 reverse box, sequential box. It has the pulley from the engine underneath and then turns through 90 degrees to drive a sprocket and chain to the back axle. the mowers brakes are on the gearbox. Which I realised is not a good idea.... if the chain drive breaks...no braking at all :S
Still havent found a marking, but after hours of searching, and cross referencing, I think it is a 700 series. Just need to get a drive sprocket now...
mowerracer (author)  difflock6 years ago
If you are unsure of what transmission you have, here's all the info you could ever want to know about Peerless transmissions:
I took the sprocket off the gearbox, and it is a 36 spline. If they will deliver to the UK, I think I might order a 12 tooth sprocket with the quick change hub from EC Distributing. Must also check that it is a 5/8" shaft on their hub though....
mowerracer (author)  difflock6 years ago
I know the people at EC Distributing personally. They are good honest people. But I would at least check at your local small engine repair shop to see if they have access to anything along those lines because the shipping costs to the UK I imagine are going to be pretty steep.
I have been to a couple of local shops... problem is, I am in a remote part of the UK so the shops are little more than a garden shed most of them :P One of them didnt even know what I was talking about :S... I really wanted to get a larger sprocket for it....the standard 8 tooth is ok for 6mph :P wanted at least a 12 if not a 15....
difflock6 years ago
I will be getting my ride on mower today :D It has had the deck removed, which is fine for me, I dont have to remove it :P Its got a 5 speed gearbox, I think with a foot clutch and a 15.5hp briggs engine :D will have to tune it I think :P
Forgot to add, a good way to get a ride on mower cheap or free, is to look for ones with a damaged or broken deck... Quite a few are sold in the UK because the deck has rotted out or it broke... And most people just buy a new mower....
mowerracer (author)  difflock6 years ago
Very true. I had a hard time finding a mower at all. I live in California and out here it stops raining in the spring and summer, thus a lot of people don't even own a riding mower. Back home in Tennessee where I grew up the grass grew like mad and people would wear out riding mowers every 5-10 years, thus it was common for a family to have a junker in the back yard. The good thing is that about 90% of the mowers in the US are made by one company- MTD, so most mowers have common components and layouts. That and they use mostly one brand of engine- Briggs and Stratton.
Fair enough. Been playing with mine today :D A Lawnking Twincut 15.5 Its got a clutch/brake pedal, and a 5 speed gearbox (+ reserve)... Stop to change gear, which is easy :P Just need to get a new set of chain and sprockets for it... Oh, and sort the engine out... Its a Briggs and Stratton Diamond 15.5hp (465cc single OHV) It churns out black smoke when revving, but stops once at the revs required... I need to get a new plug for it...its got some random NGK in it. :S Clean out the breather and replace the air filter... If it still smokes, I will whip the head off and see if it needs a decoke... Hehe....good thing with briggs engines :)... in stock trim/tune they are indestructable :P P.S. Lawn king got bought out by Husqvarna so parts shouldnt be a problem :P
mowerracer (author)  difflock6 years ago
If the engine is putting out black smoke then that would indicate that the carburetor is running a bit rich. That could be simply a matter of adjusting the choke or main jet in the carb. A lot of newer engines don't have much in the way of adjustment. The Briggs OHV engines make very good engines for this sport because they seem to hold up a lot better.

Also- if you are in the UK, that's where mower racing began and there are some of the largest groups there. I would check out this site and see if you can get together with some of the people there. They could probably help you get your mower setup. A lot of the parts we use on ours are made in small shops in the US, thus the shipping costs to the UK would be expensive. I'm unfamiliar with parts suppliers in the UK, this getting together with a British group might be very useful. Here is their site:


Lastly, I used the stock carburetor for my engine. The air filter is a high performance motorcycle filter made by K&N. It is fitted the the intake of the carb via a machined piece that bolts to the end ( another custom-made part)
Yes, I know what the black smoke means I was going to overhaul the engine and carb... Need to sort the gearbox sprocket first though...
btw, did you replace the carb on your engine? I must get a performance filter like yours :P Much better than the standard box :) Oh and forgot to add, the gearbox control on mine to select gear is on the dashboard :P even though its not a hydro... and the throttle is on the other side...a slider type with a tortoise and a hare :P reminds me of the vintage tractors we used to have :D
I cant get the original pulley of my transmission its looks rusted to the shaft or something has anyone got any ideas for getting it off.
mowerracer (author)  extrememonkeydude6 years ago
I had the same happen to me and my RAGB transmission. What I did was get a 4" cutoff wheel, cut through the spokes of the pulley, then cut through the pulley almost down to the shaft. I did that on both sides and it eventually came off. Be patient when you do this though. You don't want to damage the shaft.
traxxasman6 years ago
About how much did u spend building this not including the mower, im a freshman and am on a tight budget?
mowerracer (author)  traxxasman6 years ago
Altogether probably around $1,500-$1,800. But keep in mind this was a heavily modified, custom mower. You can build a milder version for under $500 in some cases.
mrh10236 years ago
what do u hook the puke tank up to on the motor where
mowerracer (author)  mrh10236 years ago
The tank hooks up to the engine breather. You'll see it behind the carb with the hose sticking out. I made a new breather cover with a threaded nipple coming out of it. I attached the hose going to the tank to it.
jsporritt6 years ago
hi again, what upgrades did u use to make it exede of 50-mph? like what size of pullies did u use??? also what did u do with the engine
mowerracer (author)  jsporritt6 years ago
Well, basically the entire set of instructions I have here shows the details of how to make your mower go faster and do so more safely. Read the whole post first and if you have questions I will be more than happy to answer them.
jsporritt6 years ago
also, what brand of Ride on Lawn Mower did u have for ur old one?
mowerracer (author)  jsporritt6 years ago
The old one was a Sears Craftsman, but honestly you can use any brand. A lot of guys who do this look for people who are willing to sell a riding mower cheap or sometimes give them away free. Often times if a riding mower has problems- like a blown engine- the owner will just get rid of them. Free is the most ideal. I only paid $50 for the one I have now.
jsporritt6 years ago
Hi, how much in the enddid this cost u to construct?
mowerracer (author)  jsporritt6 years ago
Overall it cost me roughly $1,500-$1,800. But I used a lot of higher end parts. The one I built previously was only about $600. Still a lot cheaper than a professional go cart which can easily cost $10,000.
so does this thing only have one gear or is it like a 5 speed
mowerracer (author)  extrememonkeydude6 years ago
Its just one gear, so its really simple.The reason I have this is because the engine shaft is vertical and in order to get the chain to the rear axle, the output from the engine needs to be horizontal. If you use a centrifugal clutch and do your gearing right, you can avoid a multi-speed transmission and a foot clutch. Makes it a lot easier to control on the track.
i'm looking at using a mower that is hydro staic any tips or should i just find a different one?
mowerracer (author)  cowboy7208420006 years ago
Unfortunately you can't use hydrostatic transmissions for racing mowers. At that high a speed it is unable to force enough fluid through and it burns itself out. You need to go with either a regular 4-5 speed transaxle or a 5 speed gearbox. Look for a peerless 500 or 700. That's the better quality 5 speed gearbox.
razor22586 years ago
were can i buy the transmissons
mowerracer (author)  razor22586 years ago
I've bought all of mine off of Ebay. I'd also look around and see if there were any mower repair shops in your area. The "good" ones will have a nice junk pile out back. Probably sell you one pretty cheap.
fordracing6 years ago
im using a 12 hp briggs do u think the parts that u got would fit mine i cant find any parts for it
mowerracer (author)  fordracing6 years ago
No guarantees, but most similar vintage Briggs briggs engines are pretty much interchangeable. When you mean parts, do you mean stock of performance? Stock parts should be extremely easy to find for it. Look up Tulsa Engine Warehouse. They will have anything you need.
razor22586 years ago
what do i need to get for my engine i want to run just a staight chain to the back but my engines shaft runs striaght to the ground what do i need
mowerracer (author)  razor22586 years ago
That's why I am using a right angle gear box because you can't run a chain straight from the engine to the rear axle. You're also going to need to get some sort of centrifugal clutch because without it you'll kill the engine when you press the gas.
fordracing6 years ago
where did u get your parts from. i was hoping a website but g team is 2 expensive
mowerracer (author)  fordracing6 years ago
A lot of the parts such as the rear axle components, brakes, wheels, tires, and so on are just go cart parts. I got mine from Acme mowersports and Turk Bros racing. If you're talking engine parts, well here's the deal: You can use a bone-stock engine if you don't have the funds. The OHV engines hold up better than the flathead engines like mine. Its just that I can't fit an OHV in my chassis because its too small. But you need to keep in mind that the stock components are not designed to handle the additional stress. But We do have some members in our club who only use stock and have had decent luck so far. I find that using engines that haven't been rebuilt seem to work better. Its not a bad thing to have a little slop in the clearances to allow more oil to lubricate the components. But again, I stress that those stock iron flywheels on rare occasions have been know to explode. So there is always that slight risk. If you do use a stock wheel, make sure there are no cracks or signs of damage period. I raced with a stock engine for a whole year and never had an issue with it. But it was a larger engine. This mower uses a smaller engine, thus I had to squeeze as much performance out of it, hence the performance parts.
fool1a1a1a6 years ago
how much did the whole motor setup cost you? i have baught stuff from g team and they are extremely expensive
mowerracer (author)  fool1a1a1a6 years ago
The whole engine with all the goodies set me back around $500. I bought a used billet flywheel, which greatly cut down on my cost.
fordracing6 years ago
did u put any performance on the motor and how do u make it sound really loud
mowerracer (author)  fordracing6 years ago
I added a few performance parts. It has a billet aluminum rod and a lightweight magnesium piston. I also installed a billet aluminum flywheel and billet "dogbone" connecting rod for the counterweights. Most of these mods were done because we run the engine 50% faster than stock speed. The stock rods, piston, and so on do not handle those speeds and will snap. The aluminum flywheel is a safety measure as well as a way to get faster response out of the engine. The stock flywheels are cast iron and can in rare occasions explode. There have been a few instances of people getting seriously injured as a result. On that final note, if you have a stock flywheel, DO NOT lighten or cut it, meaning remove material or alter it in any way. We have recently had a member in another club have serious injury done to his legs when the stock flywheel he had lightened exploded.
mowerracer (author)  mowerracer6 years ago
One more thing- the engine is loud because there is basically no muffler. It just has a straight pipe coming out about 24".
seal21776 years ago
GOOD.BUILD..keep in mind not all mowers are built this way check out over 50 diffrent builds ..to include youth model builds at www.rivervalleyracers.com....our rules are a bit diffrent and we have had great success ..no injuries and crowd in excess of 1000+..we average about 40 diffrent mowers a race I would be happy to help anyone with a build just ask for Crazytrain in the forum
buttersnake7 years ago
Very well written mate! Its so nice to be able to read an Instructable or anything for that matter that is so well written and not full of slang and all. A mate of mine had 2 or 3 riding mowers at once and made one of them pretty fast. All he did to his was switch the drive pulleys around and remove the governor and a few other small things dealing with the air intake and exhaust and all. He had to weld wheelie bars on it because the thing would stand up in a second. Just his small mods made it run about 20-25mph which was just hilarious to us. What was so strange about his was that it was so fast on top end but it would jerk the front wheels off the ground for 15 or 20 feet also. Is that typical for mowers to have such a strong top end and still have tremendous "torque" I guess its still torque but its just funny calling it that being that its a lawnmower. I am ready to find me a few freebie mowers and bring them home and get started! GEO metro motor anyone..... :)
mowerracer (author)  buttersnake7 years ago
To answer your question about torque, the reason lawn mower engines have so much of it is because when you throw the mower deck lever, the engine has to provide an enormous amount of initial torque to start the blades spinning. If you've taken one of these engines apart- even something smaller like a 12 HP Briggs- the piston is gigantic in relation to the engine. About the size of a piston out of a car. You can get a lot more HP out of a typical mower engine with mods. Top of the line builders will bore out the cylinder, install lightweight billet rods, magnesium pistons, Billet cams, high performance valve springs, billet flywheels, ignition systems out of cars and so on. They will also clean and polish all the ports, install high performance carburetors, and electric fuel pumps. I actually blew my first engine because the stock rod broke in half. I have on order a billet rod and magnesium piston with thinner rings for a tighter fit. Along with the billet flywheel, this should make it run a lot better at high speeds. Anyhow, good luck on your build, and be careful!
Thanks for the info. Sounds like you are going to have some cash in your Racing Mower for sure. My mate and I talked yesterday and we are going to both get a mower and have the same hp engine on them as a base and then we can do whatever we want to them as long as its not anything internal such as boring and new heads and all. The reason we aren't is to keep cost down, he makes more money than i do so it wouldn't be an even race seeing that he could put tons more money into than I. When we finish we are going to have best of 3 drag races, should be fun. I have to find another mower because i can't destroy the one i have, i need it! But i know allot of times you can find one that doesn't run anymore that people will just give you. The one i have a guy gave it to me because he said it just ran bad the times it would actually crank. What was the problem with the mower that this guy made out to be the worst thing ever? Fuel filter and trash in the carb. It looks really good also, clean frame and nice shiny paint.
mowerracer (author)  buttersnake7 years ago
Well... for this build I sunk more money into it than the previous build. My first build was a very mild modified machine. I spent around $500 on the whole build.On this build, I spent maybe $1,300 minus the future engine modifications. So the costs can be sporadic. Some of the more serious guys blow upwards of 5-10k per build, which to me defeats the purpose of the sport, which to give people with less cash the ability to race and keep the costs down. Ironically, I raced this weekend with a completely stock 12 HP Briggs engine that someone gave me. It actually performed really well. The key is to make your chassis as tight and well handling as possible. It also helps to keep the weight down. My build is under 200 pounds. Most are at least 450-500 pounds. So that alone is a massive advantage. Since it is also really low to the ground, I can hug corners, which is a big advantage as well. I'm guessing that you're either from the UK, Australia, or New Zealand since you use the word bloke. Sorry if I'm wrong! But if so, there are actually TONS of mower racing clubs in the UK and Australia as well as a few in NZ. In fact, the sports started in the UK, and those guys would kick our asses anyday because they've been doing it a lot longer. So you might want to hook up with some of those guys if you want to race in a group. If so, well unfortunately they don't allow suspension systems. has to be nothing but frame and tires... which is why I am very sore from Saturday's race! Good luck with what you do.
Actually im from Alabama, where i figured lawnmower racing prob started...haha. I have a few friends from AUS and over the years i have picked up on a few words they use like bloke and mate.
The sport was actually "invented" in 1973 in The Cricketers Arms pub in Wisborough Green (not far from the town of Horsham) in West Sussex, England, UK, by a group of young men bemoaning the prohibitive costs of getting involved in any kind of motorsport. They formed the British Lawn Mower Racing Association, and shortly afterwards, a northern equivalent in the form of the North West Lawn Mower Racing Association was formed. THATS RIGHT I AM ENGLISH
mowerracer (author)  buttersnake7 years ago
Alabama huh? I'm originally from TN.Anyhow, there's TONS of mower racing groups in TN.L, NC, GA, etc. So look around and see if you can find a group. One of the national champs lives outside of Nashville.
Also what I was asking about the torque was is it typical for mowers to keep the high torque numbers throughout its entire operating rpm range? I'm very familiar with small engines and design and such ( not all, mainly, motorcycle engines...which is what i run on my kart, 125cc Honda with a 6-speed) i race 125cc shifter karts. I'm actually planning on using some of the older used suspension pieces and brake setup that i don't use anymore from my kart onto the mower.
djr36 years ago
what did you use for carberation?what type of fuel?
mowerracer (author)  djr36 years ago
The carburetor is the stock carb that came with the engine. The only thing I did was order a billet aluminum adapter so I could fit the large K and N air filter. You can actually run it with the stock air filter but putting on a performance air filter wil give you a bit more power.
for my school project i need to use a broken down lawn mower from the dump and make it run what do i need to do to make it run and money is no problem and how do i know what can fit on the chassis.
mowerracer (author)  Big Martinis6 years ago
If the engine doesn't run there's three basic principles to follow for getting an engine to run: Spark, Compression, and fuel. Check to see if there is spark when you spin the flywheel ( taking the spark plug out first) and attaching the end of the spark plug to the plug wire. Let the plug dangle next to something metal on the engine. If you spin the flywheel and see a spark, then you have fire. If not, check the points ( on older engines usually prior to the 80's) or the coil which are on newer engines. If you have spark, check for compression. That's pretty easy to do. If you spin the flywheel with the plug installed and one stroke has resistence, then you likely have compression. If the resistence is minimal or non-existent, then something is going wrong which could mean worn rings, a worn cylinder, worn valve seats, etc etc. If you have both spark and compression, check the carburetor. Clogged, dirty, and gummed up carburetors are the most common problem with old engines. If the carburetor isn't getting fuel to the engine ( you will be able to tell if the plug is dry ) then take it off and clean it. That usually means disassembling the whole thing and cleaning out all the jets and so forth. These are bare-bone basic suggestions. If you don't have experience working on small engines, buy some shop manuals or find someone that does and learn how to work on them. Its kind of a science and artform. But get some practice at it and you'll be good to go.
Merkatroyd6 years ago
When I got my brake calliper, it came with allan wrench bolts on it that mounted the brake pads. Am I supposed to use these?
mowerracer (author)  Merkatroyd6 years ago
What kind of brake system did you get? Typical cart brakes come with a caliper that is split in two. You're supposed to mount the brakes to the frame with two long bolts. These mounting bolts will hold the caliper together. The rotor of course goes in between the caliper. Look up diagrams for cart brakes and you'll get a good idea of how they go together.
tiddilykid6 years ago
for a beginner what do you think would be a good base model to start with.. would you recomend on putting a moped engine in the thing as a replace ment
mowerracer (author)  tiddilykid6 years ago
Well, basically any riding mower that you can find will work. As there are several classes of racing mowers, you could start out in a stock class which is the least modified class requiring the least amount of money. Look up the rules for ARMA. Here's a link to those rules:


Try putting up a want ad for a riding mower. You'd be surprised at how many people will either give away an old riding mower or charge very little to get rid of one that's been sitting in their garage for years.

Lastly, a moped engine isn't going to have enough power. Lawn mower engines have an enormous amount of torque because they have to turn a set of blades as well as propel the mower. A moped engine is typically under 50CCs versus even a small 12 HP Briggs engine which has 128CCs. Stick with what comes with the mower and also because anything other than an engine that was designed to fit lawn mowers is not allowed anyway. Good luck!
do you like my new picture
Just read the tutorial. everything you need to know is already here.
aaronsname6 years ago
how war your wiring system set up?
mowerracer (author)  aaronsname6 years ago
Here's a simple diagram that shows you how. Not much to it: A solonoid, starter, cutoff switch, and battery.
mowerracer (author)  mowerracer6 years ago
pegleg1996 years ago
mowerracer (author)  pegleg1996 years ago
All told, it took me around 8 months to build. But that's because I work 50 hours a week and could only work on it on Saturdays and occasionally at night. It also sometimes takes a long time to find parts. I live in a metro area and out here its not nearly as easy to find the appropriate parts as I could when I lived in a rural area. Expect around 100 hours or so for the average build. Builds like mine are almost entirely built from scratch, so there's a lot to do.
slayercr236 years ago
I came across this hobby awhile back and have decide to build a raceing mower. I've done my home work and got a mower. Rigth now im tuneing the engin and cant find the govenor. So i was wondering if you could help? Oh and i have the same briggs as you do in your pics, but mines a 14.5hp. So if you could help that would be great!
mowerracer (author)  slayercr236 years ago
If you look on the same side as the Carburetor, you'll see a 4-5" arm that has a rod connecting it to the carburetor. If you start the engine and pull back on that arm, you'll notice that the speed increases. What you'll want to do is remove the governor because you'll be controlling the speed. Here's what to do: A: Pull the plastic air cleaner box off the carburetor. There are two screws holding on the front of the carb. That and a few that you'll see when you pull the air filter top. That makes it easier to get at things. B: Its preferable to remove the entire governor mechanism, which means taking the bottom pan of the engine off and removing the spinning counterweights that controls the governor arm. To do that, there is a small bolt that tightens the governor arm to the governor shaft that goes through the case. With that removed, and with the pan removes, you can slide it out. remove the brass sleeve the governor shaft goes through with a punch. Fill the hole with JB-Weld or some other automotive grade epoxy. C: If you don't want to do that, you can just remove the governor arm, but just be aware that that could potentially cause problems, but not usually. D: With the governor removed, you'll see a lobe that sits on the top of the carb. It has 2-3 holes for linkage. That's your speed control. What we generally do to control it is to get a bicycle brake lever and cable and then use a spring to pull back on the lever so that you have a spring-loaded gas lever that attaches to the steering wheel. Hope that helps!
OK, so basically if I don't want to take the engine apart all I have to do is take that arm off?
mowerracer (author)  slayercr236 years ago
That's correct, but be aware that when you do so, the governor counterweights inside the engine are going to be flopping around a lot. There has been on occasion where they have broken as a result and cause engine damage. I ran an engine like that for awhile and had no issues. Its actually pretty easy to take the engine apart. Nothing to it really and you can use gasket maker to seal it back up. Look on Tulsa Engine Warehouse on their site and do a parts lookup for your model engine. They have nice exploded diagrams of engines which will give you an idea how to do it. Short answer- yes, you can just remove the arm.
hozerhead696 years ago
how fast can you go
also, what kind of air filter is that on there?
mowerracer (author)  skatermatt116 years ago
Its actually a K and N performance filter for motorcycles. I bought an adaptor made by a company called EC distributing. They cost about $20-$30 each. You don't have to have it per say, but it helps the carb breath a little better.
hi, great stuff what youv done, i was wondering what diameter the RAGB output shafts were and where i can find a centifugal clutch, i have a 20hp twin cylinder briggs and straton. thanks
mowerracer (author)  skatermatt116 years ago
The output shaft is 5/8" and the sprockets are a 14 tooth for the input, 12 tooth for the output.
can you give me some tips on bulding a racing lawn mower and i got a lawn cheif
what kind of axle did you use
man your lawn mower is cool
Fail-man6 years ago
Hi once again sorry to bother you all the time but you have all the knowledge. I assume you use go-cart parts but can you use cross and 4wheeling parts as well or is it best to use go-cart parts thanks your awesome Thanks a dude from sweden
Fail-man6 years ago
thank you very much sir your a realy god "explainator" that help alot. The thing im must focus on most is the FRAME BRAKES MOTOR(SPEED) STEERING????? And ive located a old HUSQVARNA thats abaout 3-4 years old can you yuse that or will it be to fragile thaks sir sorry if i repeted my Questions last time ive writed to you your awesome thaks for the help see you later alligator Much thanks A dude from sweden
mowerracer (author)  Fail-man6 years ago
Well, 3-4 years old isn't that old. Just check the frame over for rust and other structural issues. Since you'll be reinforcing the frame and replacing much of the other components, most of the original mower will likely be discarded anyway. I believe MTD makes Husqvarna riding mowers anyway, that is unless they have their own that is made in Sweden. I know that the ones they sell here all have Briggs and Stratton engines. But as mentioned, most any mower will work because in the end, only the cosmetic appearance of the original mower will be left.
Fail-man6 years ago
Hi sorry im late to ask the questions ive had to go for a while so my question(s) are 1:with is the best mark Westwood Lazer Honda Wheel Horse/Toro John Deere Mountfield Lawnflite Murray Countax Rally AYP Ariens Simplicity. With is the best mark for Lawn Mower Racing 2: can you ride the mower without change it to much (im not lazy i just wonder sir) 3: Can you putt a (for exampel) Kitaco 150cc cross motor in it? Or will it brake by the power and the chassi can you adjust it as you want or is that illegal and can it be as fast as you want sorry im not very familiar with the rules thanks sir your awesome!!!!!!!!.......... O Sir Siiiiiir i forgot one thing do you HAVE to change it much so it will not braket or is that a must. Thanks sir Your Awesome A dude from sweden
mowerracer (author)  Fail-man6 years ago
The answer in regards to what brand -or mark- of mower to use is that any will work. I'm not familiar with some of the brands you mentioned but I assume most are similar to US-spec machines and have either Briggs and Stratton or Tecumseh engines and some sort of transaxle. The second answer is that making a stock mower fast without modifications is pretty dangerous. The reason my mower is so heavily modified is to deal with the additional speeds and stress. Even as mine is, I still have things break out on the track. So if you are going to make a racing mower, I would still highly recommend you make upgrades to the brakes, steering, frame, and so on. To give you some ideas on how to do this, you can check out this site: www.heymow.com and click the link for the build section. You will see many examples of mowers that have been made into racing mowers plus a lot of members of the site who will answer your questions as well. Hope that helps.
Fail-man6 years ago
Thank you very much that helped allot thanks your awesome man your the best thanks again for the help................ But can I ask you an other question??????
mowerracer (author)  Fail-man6 years ago
sure, what's the question?
mowerracer (author) 6 years ago
The crank case is basically just the engine casing, which supports the crank, rod, pistons, valves and everything else for the engine. The crank case tank I'm referring to above is meant to remove excess oil being pushed out of the engine by crank case pressure. This allows the engine to breath easier. Hope that helps!
Fail-man6 years ago
Hi mowerracer your super i love your ideas and work but i have i question what is a crank case sorry im new and i love motor sports especially lawn mower racing thank you. A dude from sweden
What is your tire and rim size? Complete sizes. _X_X_. Thanks.
mowerracer (author)  derekonderdonk6 years ago
These are 6" rims using 11 X 5.5-6 grooved ties made by Burris. They are go cart wheels and tires. The tires and wheels can be bought here: http://www.tbrwins.com/catsearch/frsearch.mgi
Was it these rims: "6 X 6" diameter VanK Wheel - Powdercoated Black Finish/2.5" Backspace"?
AHolland6 years ago
where can i get a dogbone?
mowerracer (author)  AHolland6 years ago
Look up G Team racing online. There's a guy there that makes them using a CNC machine.
You can actually buy this straight from ARC. http://www.arcracing.com/servlet/StoreFront You'll have to email them and have them send you a catalog that comes in a pdf. I think the dogbone is part number 6200.
what kind of tires and rims did you use
mowerracer (author)  yamahabanshee3506 years ago
These are 6" rims using 11 X 5.5-6 grooved ties made by Burris. They are go cart wheels and tires. The tires and wheels can be bought here: http://www.tbrwins.com/catsearch/frsearch.mgi
what kind of tires do you run
MikeJohnson6 years ago
i got a racing lawnmower and i need a different steering system as the one that i designed isn't to hot. i ve been thinkin of ur set-up and think im goin try it. do u now if it will work all right on a heavier mower? im also wondering about the pitman arm coming from the wheel, can u tell me everything u did for it? angle? ofset?......... Thanks Mike
pnelson_896 years ago
i have a toro 910 idk what year? would that be a good lil runner sence its so small?
mowerracer (author)  pnelson_896 years ago
It doesn't really matter what type of mower you happen to find because by the time you get through with all of the structural and safety modifications, very little of the stock mower will be left. As mentioned, the stock steering, brakes, and wheels are worthless so you will need to do the proper upgrades.
fossheim136 years ago
does it make the lwnmower go faster
mowerracer (author)  fossheim136 years ago
As I've mentioned in this instructable, its a very bad idea to make a stock lawn mower go faster. Doing so is dangerous. I wanted to make that very clear. Understand that these racing mowers are almost entirely custom built for handling greater speeds. And no, they do not have blades of any kinds attached.
fossheim136 years ago
do yuo know abaot som other easy tings i kan do to make it go faster
fast-dude6 years ago
how fast does yours go?
mowerracer (author)  fast-dude6 years ago
I've never clocked it. My guesstimation is around 35-40MPH. But this year I have made upgrades and will be doing test runs at our first group event this weekend. I'm shooting for 50MPH.
do yuo know abaot som other easy tings i kan do to make it go faster
i have a toro 910 idk what year? would that be a good lil runner sence its so small?
i do not no i no it is 11hp
fossheim136 years ago
hawe yuo added a stel plate araund de topp
mowerracer (author)  fossheim136 years ago
Are you talking about what the engine sits on top of? If so, I just used the steel pan that engine sat on which came with the original mower. But you can also use steel square tubing and drill holes for the bolt holes. This depends on your class. As mention, I am running in an FX class which means I have more liberal, lax regulations.
What kind of sprockets did you use? How do they stat put on the shafts?
mowerracer (author)  derekonderdonk6 years ago
They are just regular 5/8" ID sprockets that I bought from www.mcmaster.com. Just look up "sprockets". They use set screws that you tighten after they are slid onto the shaft, and that it what holds them in place.
griffy-poo6 years ago
Can I use your instructions to make a racing lawn mower out of any kind of riding lawn mower or would I have to use a late 60's Grants mower when going by your instructions?
mowerracer (author)  griffy-poo6 years ago
These instructions are meant to give you a general idea of how to build a racing mower. Since most of these are one-off type builds and mowers can be drastically different, what yoiu build and how you build it can vary greatly from my build or anyone else's. If you have any questions about a type of mower, let me know and I'll see if I can help.
Would a ' Westwood Gazelle ' work on these instructions?
mowerracer (author)  spikeymikey1086 years ago
Well... short answer is that any mower can be turned into a racing mower. But there are different types of chassis out there. Most made in the last 30 years or so use a stamped steel frame while others like mine use a welded steel frame. You can make one out of both, and in some cases the newer machines work better because they are lighter. Check out www.heymow.com and look at the build section. There are many there that use both styles as a base. That'll give you some ideas.
where did you get those tires
mowerracer (author)  grasskicker1016 years ago
They are Go Cart tires, so look up any site, or even ebay and look for them. You can sometimes find them used, but as for racing mowers, make sure and go with grooved dirt tires because slicks will not work at all.
chivesg56 years ago
you took the gavaner off that way did it not blowup
fast-dude6 years ago
how long is the 1x1" square tubing on top of the axle hangers that go most of the way down the frame?
mowerracer (author)  fast-dude6 years ago
I don't exactly recall. Most of the pieces were cut to fit as I went. The frame is not super-accurate. Lots of eyeballing.
fast-dude6 years ago
so did it come with everything you needed to have it go over the engine?
mowerracer (author)  fast-dude6 years ago
No, I had to fabricate the steering connecting rods, pittman arm, and the hubs that house the bearings for the shaft that goes down the front of the mower frame to the axle. The hubs are made from pieces of 1/5/8" steel pipe cut into small pieces. The bearings are from a hardware store. The steel rods are just raw steel rod stock, and the heim joints ( ball socket joints) are welded to the ends of the pieces so they can swivel. Making the steering system is probably the most difficult part of the build and expect to have a lot of trial and error. Handling is everything, much more so than speed and power. So get it right the first time and you'll be ahead already.
fast-dude6 years ago
where does the dogbone go?
mowerracer (author)  fast-dude6 years ago
If you see the pic of the counterweights- the large chunks of cast iron with the crankshaft going through them- they go in between them. They come apart with a single bolt on the bottom. If you dismantle the engine, you will see the old dogbone there.
fast-dude6 years ago
what hook up for the steering did you choose?
mowerracer (author)  fast-dude6 years ago
This is a center steer setup. The steering arm goes over the top of the engine, down the front, and to the front center. This is actually how the mower came, so I just stuck with that system. On other builds, people will run the steering shaft UNDER the frame with a pitman arm attached underneath for the steering arm which runs to the right side typically. Check the Acme mower web site because he has both setups as well as some diagrams for setting them up.
fast-dude6 years ago
on the frame where the steering wheel is
fast-dude6 years ago
where did you get your axles at? and what is there lengh?
mowerracer (author)  fast-dude6 years ago
The front Axle is from a site called Acme mowersports from TX. http://www.acmemowersports.com/
I got the rear axle from there as well, but its a typical 1 and 1/4" go cart axle. They make a chrome moly and aluminum axle. Go for the chrome moly. You can get these anywhere that sells go cart parts. The axle is 40". Just remember that the max width is 38" from tire to tire so you'll want to get one as close to that as possible.
fast-dude6 years ago
im thinking of building my frame by hand but i kinda need to know a rough estimate of the lengh and width of the one in the pics? can anyone help me with that?
mowerracer (author)  fast-dude6 years ago
The length is around 44 inches and around 17" wide for the middle, 38" from wheel to wheel on the front and back axles.. It is TINY, but I'm kind of a small guy. If you build your frame and plan to race, you need to download the specs from either the USLMRA, or ARMA which are the two largest racing mower organizations. They have all of the max width, height, wheelbase, and so on. Build to those specs and you'll be good because at these events, they WILL check your dimensions, so you'll want to make sure that they are correct.
fast-dude6 years ago
i can find a late 60s grant mower any where is there any others with almost the same style
mowerracer (author)  fast-dude6 years ago
It doesn't really matter what brand you use since when completed, hardly anything of the original will be left. All that's left of mine is part of the frame and the hood. The frame is almost all custom. Other small riding mowers to look for are: Rugg, Mustang, Huffy, and even a few older Sears. Just look for SMALL riding mowers and see what comes up.
chivesg56 years ago
how thick is your frame
mowerracer (author)  chivesg56 years ago
The frame is all 1/8th" steel tubing. But some guys use the thin wall stuff and it apparently holds up fine.
fast-dude6 years ago
so how much do you think it costs to build one of these
mowerracer (author)  fast-dude6 years ago
This particular mower cost around $1,500 all together. The little stuff ads up quick: Tires, clutch, engine, engine upgrades, raw steel, wheels, brakes, and so on. But the good news is that you can definitely build them much cheaper. My first build was a mild mod of a Craftsman with an Acme front axle, mechanical brakes, and general frame reinforcement. I used old Go-cart wheels and tires for the back, the stock wheels for the front. I spent maybe $600 for that mower and sold it for $650. You have a lot of leeway as far as how much or little you want to spend. But if you go for cheap, sometimes it requires being more ingenuitive. For example, instead of buying a go cart brake system, some people use a brake system off an old junked motorbike.
were did you get the tires and rims
123-abc6 years ago
If i took the governer off a stock mower that had a 12.5 HP Briggs and Stratton would it make it go faster?
mowerracer (author)  123-abc6 years ago
It would, but if you're going to make a mower faster, you need to make upgrades to the rest of the mower such as the brakes, steering, and frame because in stock form, they're only made to go 2-4 MPH. If you made a stock mower faster, that could be a serious safety issue.
chivesg56 years ago
whan u walded things to your frame did your frame worp
mowerracer (author)  chivesg56 years ago
No, the frame is made of fairly thick square tubing.
hey i found my clach
mowerracer (author)  chivesg56 years ago
good to know!
Do you run race fuel in that motor or any octane booster?
mowerracer (author)  toyota_smasher6 years ago
I just run regular unleaded because these are just lawn mower engines and high octane isn't going to make that much of a difference.
where did you get those wheels and tires? thanks justin
mowerracer (author)  toyota_smasher6 years ago
They are go cart tires and can be found on most any site that sells parts for them. I got mine from a site called Turk Brothers racing. If you build for another class such as an AP or super stock, you can use lawnmower wheels and tires, which are much cheaper than Go cart tires, which can cost around $50 each. Look on ebay too. Sometimes there are used tires out there. Lawnmower racing doesn't put too much wear on tires, so even a used tire will last several years.
mrdelaney216 years ago
I was wondering if anyone has a 1:1 90 degree gear box for sale with 3/4in shafts if not where can I get one and will a split box with 2 out puts work. please email me mrdelaney21@aol.com thanks
chivesg56 years ago
were can i git a clach like yours but i need 1 4 a balt
mowerracer (author)  chivesg56 years ago
Mine is called a Titan clutch. But Noram also builds centrifugal clutches. Look those brands up online and you will find sellers. Clutches that use belts are harder to find. if you can't find one, you can weld on a belt pulley instead.
oscar916 years ago
hey im building one and i rebuild the engine but when i stated it it would then die i tweaked on the carburator but still samething kickass mower
mowerracer (author)  oscar916 years ago
Well, did you clean the carb? It doesn't take much to make them not run correctly. Take it apart and clean all of the jets. Also make sure that the float and needle works properly. Also check your spark and timing. Sometimes the flywheel will shear the flywheel key, which is made of soft aluminum. If it does, that can also cause problems. If it has a weak spark, it could be a faulty coil, or points if it is an older engine. Just run through the basics: Fire, Fuel, compression, etc etc...
chivesg56 years ago
hey i am bulding a racing lown mower can u give me tip
mowerracer (author)  chivesg56 years ago
Take a look at heymow.com and read some of the builds under the build section. Most are highly detailed with pictures and instructions.
jaglusby6 years ago
I was wondering if you could weld a frame like the one you have
mowerracer (author)  jaglusby6 years ago
If you mean just fabricate one from scratch, you can if the class allows it. Mine is known as an FX class, which means experimental class. Most of my frame is made out of tubular steel.
mowerman636 years ago
do you think it would be a good idea to boar out a 18 horse craftsman motor? and how would i do it? its got dual carbs and twin cylinder? Would just like it for speed so i can drag it..
mowerracer (author)  mowerman636 years ago
If you have a V-Twin, I'd probably just let it be because these engines come out of the box with quite a bit of power. In fact, the stock pistons and rods are actually much better than typical Briggs engines. The cost of boring out that engine would be expensive. Lastly, please remember that mowers that are in stock condition should not be raced because the brakes, steering, and frames are not designed to handle the speed. Thus make sure and research how others have built drag mowers. There's a few sites out there that show you how. Namely heymow.com. Unfortunately my mower is a circle track racer thus I'm not exactly qualified to discuss drag race mowers.
AHolland6 years ago
were could I get a axle like that at a reasonable price?
mowerracer (author)  AHolland6 years ago
The front axle is made by a guy in TX who runs a company called Acme Mowersports. The whole front axle with components for the steering was around $125, which is really reasonable given the cost of all the components and having to set your own inclination and caster. http://www.acmemowersports.com

The rear axle and parts can be had from any go cart supply seller. I got mine from Acme as well because his prices are decent, plus he is a good guy to deal with. Go for the 1" 1/4" size axle because it is the most common size thus you will have an easier time getting things like brakes, bearings, and sprockets to fit it.
ArdenW6 years ago
Where do you buy those type of tires. I live in Canada and can`t find a dealer. Thanks
mowerracer (author)  ArdenW6 years ago
I bought mine online from an outfit called Turk Bros. They are go cart tires, so just look for go cart parts and accessories and you should be able to find them. I'd also check Ebay since people sometimes sell NOS or used tires, which can be a lot cheaper.

underbird76 years ago
Hey man, i really like this. My grandpa is giving me his old MTD in a few days and ive been thinking of making it off road or like this, and im really impressed with this. Can i ask how much money was put into this and time? im still a high school student, but i love racing so this would be something that id build over the summer. Is it really hard as it seems? Well... it doesnt really look too hard, but looks like it takes alot of time. I dont know what kinda MTD it is, like, a 1995-2000 i think.. more like a 1997 or 8. Its atleast 10 years old. What would I be looking at as parts and labor and cost? Thanks alot man, I really like you ride, looks like alot of fun.
mowerracer (author)  underbird76 years ago
There's actually a site for " All Terrain Mowers" here:
As far as costs, it can vary greatly. I chose to use mostly high performance, high grade parts because we really beat these mowers up on the track. The clutch, engine, transmission, steering system and so on all have to be top-notch. Even so, I'd say that every other race I break down, which is common. Mine cost probably around $1,800 altogether. But I didn't have anything. No steel, no mower, no parts, etc etc. But a lot of guys who make these seem to have lots of stuff laying around. So if you can salvage steel and other parts, you can make it cheaper.

My first build was a mild Sears build and cost me maybe $700, so less than half that of this build. My current "Mowchine" took 9 months to build , but mostly because I have a full time job. This will be my 2nd year with this mower and all I've had to do to it so far is change out the rear sprocket, order new bearings for the steering and steering wheel, and a new tire. So if you build a good one that's easy to upgrade, you can keep it running competitively for years.

This is still one of the cheapest motorsports out there, but I understand it can be hard in HS.

The off road builds are really different and require different components. So you might want to check out that site.

Anyhow, good luck!
yea, would changing the like.. sprockets in the front and back like put on smaller sprockets for the chain drive increase the speed at all? probably not much, but would putting on smaller sprockets on the front and rear make it faster? im kinda trying to do this thing cheap and not having to change anything majorly, just want something that would go like... 20-25 mph maybe. any ideas?
mowerracer (author)  underbird76 years ago
The basic principal of changing out sprockets and pulleys is that you are altering the gearing ratios. So if you were to remove the original smaller engine pulley and replace it with a larger pulley while conversely swapping the larger pulley in the back with a smaller pulley or sprocket, then the speed would be dramatically increased. But... As I mentioned in the introduction, trying to modify a stock mower without changing the brakes, steering, frame, and so forth would mean you're basically making a mower that was manufactured to crawl along at 3-4MPH suddenly go 25-30MPH, which is pretty dangerous since none of the stock components are made to withstand the additional stress.Thus I wouldn't recommend making a mower go fast without making safety modifications. Many of these components such as the axles can be manufactured with raw steel and go cart components. If you can't afford hydraulic brakes, there are cheaper mechanical cart brakes available. Keep it safe and do some research on racing mower builds. Check out heymow.com and look at the build section to get some ideas.
OK one more time let me explain what I am trying to accomplish, we are in the process of building two mowers first is a drag mower with two 17 Hp Kaw engines running on propane which is 104 Octane. So I am try figure out how to hook up one engine to one rear wheel and the other to the second rear wheel. The other will be a racing mower. or as we call it in the car world flat track.
mowerracer (author)  propanemower6 years ago
Hi there, Sorry I've been out of town. Anyway, the RAGB I used is actually an International Snowblower attachment, but in reality, you can use just about any RAGB as long as it will fit in the chassis and be either a 1:1 ratio or even a 2:1. You can find them on Ebay. You can also use RAGB's that came off old mower decks. These are generally cheaper. The axles, brakes, and sprockets are all from go cart parts web sites. Just look up go cart axles and get components that fit 1 1/4" axles because that size axle is most common. I got all mine from Acme mowersports. As far as hooking up two engines, that's going to be extremely difficult to do because getting them to sync would be a nightmare. That and I'm not sure I'd suggest propane since if you wreck then you would have the equivalent of a large bomb strapped to the back if that tank were to get punctured. Stick with plain ole' gas.Its safer. Besides, some of the racing mowers out there will go well over 60-70MPH using just one engine, and in some cases just a plain single cylinder 12HP briggs. So often its more to do with the chassis and not necessarily the engine. Anyhow, good luck with your build and play it safe.
Also the rear axle set up that you used where do you find all the parts
I do have one question to your build up where do you find a RAGB that will fit a mower application.
mccrank1816 years ago
what kind of mower was it origialy?
mowerracer (author)  mccrank1816 years ago
It was a Grants. But there were lots of manufactures that made small mowers like these. They include: Huffy, Sears, Rugg, and even Wheelhorse.
BillBenner6 years ago