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.

Step 1: Configuring the build.

The next step is probably one of the more difficult parts of the build: configuration and finding parts. Building one of these is sort of like building a small car with all its various systems. Since all of these racing mowers are one-off type builds, finding the parts that will work can be a pain. I've had a lot of questions about where the tires, clutch, and right angle gear box ( transmission) comes from. the gear box can be found on ebay. The tires are go cart tires and can be found online on any site that sells go cart parts. The same is true for the brakes and rear axle components. The front axle is a custom unit built by a company called Acme Mowersports.

A list of parts needed for this build are:

A: Engine
B: Transmission ( right angle gearbox)
C: Centrifugal clutch
D: sprockets
E: Front axle and spindles
F: Rear axle and axle hangers
G: steering wheel
H: Brake system
I: chain
J: electrical components
K: Wheels, tires, and hubs
M: Gas lever
N: high endurance engine components

Many of the others need to be made by hand. One thing that's helpful is that many of these components such as the rear axle and hangers,wheels, hubs, spindles, and brakes are basically go-cart components. Some golf cart and motorbike components work as well. Sprockets and such can be had from sites such as Mcmaster -carr.

Once you get all the parts, the build actually goes pretty quickly.
Hi i have a 23hp red snapper and i wanted to use it to get the mail and dump garbage. What would i have to do to it? Thanks
I have a 2006. Huskee 18.5 briggs and stratton and wanting to place a racing air filter on itinstead of having the reglar one on it how would i go about.
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.
Hello traced1. I am working on building a racing mower would i have to modify the whole mower to catch a little speed. On a 18.5 hp briggs and stratton motor. Mtd huskee
<p>Great job! I had to comment on your connecting rod incident.</p><p>I had something similar happen to a stock 14HP B&amp;S engine on my Snapper. I was mowing right along and all of a sudden the engine just died (no bang or any other dramatic sound). </p><p>I got off my mower and saw this large hole in the engine block and oil everywhere. Upon investigation it appeared that one or both of the nuts that holds the connecting rod to the crankshaft had vibrated loose! Doesn't B&amp;S use Lock-Tite on connecting rod fasteners from the factory? I could not see any trace of Lock-Tite (red/blue/green).</p><p>I ended up buying a used Kohler engine for $150 which was older than the mower and it was still running great until I sold the Snapper about a year ago.</p>
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.
<p>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.</p><p>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.</p><p>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.</p><p>Wasn't talked about here, but always lube the cam lubes and bearings with assembly lube (STP oil treatment works too) when assembling engine. </p><p>Hope this helps some of u out.</p>
Im working on building a race mower and im wondering how the build will cost
<p>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.</p>
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.
<p>What kind of welder will work for welding on the frame?</p>
<p>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&quot;. 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.</p>
<p>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 </p><p><a href="https://www.youtube.com/watch?v=PRUrSpy69fg" rel="nofollow">https://www.youtube.com/watch?v=PRUrSpy69fg</a></p>
Where did you get your RAGB from? and how much did it set you back?
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.
<p>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.</p>
<p>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 <a href="http://lawnmowerwizard.com/featuredarticles/worlds-fastest-lawn-mower/" rel="nofollow">http://lawnmowerwizard.com/featuredarticles/worlds-fastest-lawn-mower/</a> it's frankly ridiculous!</p>
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: <br> <br>http://www.amazon.com/Starter-Tecumseh-36680-33605-35763A/dp/B002T4I3RW
where did u find/get a high torque starter? i have a couple of racing mowers myself. thank u in advanced. :-)
I was wondering what brand of clutch you have or recommend for using and how wide is you're axle
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
<p>where did you buy most of your parts (brake, clutch, ect..)</p>
<p>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 ?</p>
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.<br>
<p>how did you connect the engine to the gear box, do you have pics on that</p>
<p>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</p>
<p>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...</p>
<p>I am not sure which is more impressive; your project or your very excellent narrative. My compliments on both efforts.....</p>
My uncle has a 340cc 4 stroke and my dad has a 370cc 2 stroke which one<br>Should I use and I am using one of these engines<br>For racing can I have some<br>Advice.
What kind of engine and what size did you use<br>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<br>You guys have?
Hay I'm a ten year old <br>Kid and I always wanted <br>A Lawn tractor do any<br>Of you guys/girls now<br>Anybody in Nova Scotia<br>With a lawn tractor for sale<br>Let me know Thanks
how to fast does it run?
This is a great Instructable, but you need to add a main image for the project!<br /> <br /> Please do that, and reply to this comment so I know when you are done.<br /> <br /> Thanks!
Wow! Just gave me another thing to think about building!
What kind of clutch did you get and where did you get it?
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 <br> <br>thanks <br> <br>Its a Wizard dont know the year
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?
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). <br> <br>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. <br> <br>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. <br> <br>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.
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 &quot;mower&quot; 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.

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