Introduction: How to Make a Really Cool Gas Powered Motor Bike

Picture of How to Make a Really Cool Gas Powered Motor Bike

make a cool bike that make a great speed of 20 to 30 mph ( depends on CC of
engine too )


fishing line
a box of straws
a small box
a Bike with hand brakes
a bike rack that connects to the seat   
a couple different sized chains
and a 49cc to 100cc engine

if you get a chain saw engine it will have lots more torque and power,
if the engine has a clutch it works better   

Step 1: The Engine

Picture of The Engine

I mount the engine ( green ) on the rack of the bike
with the gas ( red ) tank strapped on to the box ( yellow ) strapped to the rack ( orange )

Step 2: The Throttle

Picture of The Throttle

The throttle on the engine should be near the carburetor and it's a little lever that I tie fishing line to

I tape straws ( blue ) on the side of the bike running fishing line through them,
the hand brake for the front tire disconnect it from the brake the tie the remaining end of fishing line to the brake handle

Step 3: The Chains

Picture of The Chains

Take a couple chains until you find one that fits tightly and snugly 

In the picture it is running from the engine to the back gear 

Step 4: Starting Up

Picture of Starting Up

Pull the handle with the cable to start the engine then test your throttle by puling on it like a brake

then test ride


Wolf321 (author)2016-03-18

It would be very helpful if you could add pictures or videos of your build so that we can see how yours turned out and build ours to match that.

DOMIN8ER (author)2012-05-26

hi i bought a 66cc engine from dragonbikes its an australian company the engine looks sweet runns ok when it starts ive replaced the plug the filters but or some odd reason i ride about 5ks then bang it bogges out n dies then wont restart (been late for work many times)i dont push it hard followed the manufactures suggestions n still wont run correctly and for long any help plzzzzzzzz thanks n my fuel mix is 40:1

Wolf321 (author)DOMIN8ER2016-03-18

Unless you have a transmission, it sounds like you could have a bad gear ratio. I recommend trying to add a clutch and shift lever, but that might be hard...

Kcip (author)DOMIN8ER2012-08-29

Domin8er, you are likely pulling vac in the fuel tank. Next time it bogs on you, quickly unscrew the fuel cap and it should start running again. If this is the problem, drill a very small hole through the center of the cap to let air in while you are riding.
Hope this helps.

bmueller3 (author)DOMIN8ER2012-08-15

You may have to steep of a gear ratio or the motor is blown. Take the spark plug out and put your thumb on the hole and pull the cord a few times. If you feel no pressure then you need a new motor.

philupk (author)2014-12-03

also, where do i get a chain sprocket that fit my chain and engine?

philupk (author)2014-12-03

how do i attach the motor to the bike rack? i have a chainsaw powerhead.

LiquidLightning (author)2011-12-20

I think you may be better off using actual bowden cables and connecting to an unused brake lever.

rimar2000 (author)2010-08-13

Congratulations, this is a nice work! But I think a 100 cc engine would be too much for a bicycle, a little dangerous.

Wesley666 (author)rimar20002011-05-23

Not at all, if it's mounted inside the frame portion rather then on the back, you can go with up to about 300cc. Look up motorized bikes on YouTube, then are tons on there, most are a 196cc 5-6.5 hp motor.

I do believe he meant that it would be too powerful, and not a space consideration. You can mount a pretty large engine to the back of a bike, much larger than an inframe.

Not at all. In fact something around 200cc 4 stroke or 150cc 2stroke would be ideal for a bike. If you adjusted the gear ratio you could get good acceleration and top speed. Also, if you did go with an engine of that size, how much you ate for breakfast would not affect the top speed of it. (That is a joke, but honestly, small changes in weight can have noticeable changes in speed for 49cc engines).

Also, I suggested mounting anything larger then 100cc down inside the frame as it lowers the engine placement and would make it more stable, and it would be very noticeable change too. Having a 30 lb weight above the back tire will make the thing want to tip even at speed, but if it's placed low in the frame, at speed it should do what an actual manufactured motorbike would do, which is continue in a straight line. If you have ever seen a video of someone falling off the back of a motorbike a speed, the bike will continue on down the road until it hits something. Even when they slow down to whatever speed they will do at idle, it's not enough to tip them. If the engine was mounted above the back wheel and the driver fell off the bike would immediately tip. I am not saying that is the purpose of repositioning the engine is if the rider falls off, but because if that's the change in how the bike acts without a rider, then with a rider, it makes it much more stable and easier to handle.

rimar2000 (author)Wesley6662011-11-18

You can use perfectly a V12 motor!

Wesley666 (author)rimar20002011-11-18

Very cool, but a tad small for a bike. I got a big V12 in a 1987 Jaguar Vanden Plas. That one would be much too big for a bike! Haha!


Also, modifying the frame will allow a bigger engine, to a point, there is always a limit. If the engine won't fit in the frame even if it's been modified somewhat to make the area larger, DO NOT mount it above the back wheel. Something that size will be extremely hard to handle and will be very dangerous! The biggest of engines you could put on a pedal bike would have to be mounted in frame otherwise the bike would be too difficult and too dangerous to ride.

TSC (author)rimar20002011-06-07

Were does it say a 100cc?

rimar2000 (author)TSC2011-06-07

TSC, It say 100cc in Introduction:


fishing line
a box of straws
a small box
a Bike with hand brakes
a bike rack that connects to the seat
a couple different sized chains
and a 49cc to 100cc engine

TSC (author)rimar20002011-06-07

Oh yeh!

Koolaide58 (author)2011-07-18

you will need at least 20 to 1 ratio better 27 or 28 to 1 or the clutch will burn out .
I have buils one so it took several trys to get it right .but it will take off with my 230 lb but on it and not have to peddal at all and run 25 mph easy if you want to go that fast ?

abell18 (author)Koolaide582011-10-21

what kind of ratio are you talking here?

LiquidLightning (author)abell182011-11-17

Gear ratio, a 27 to 1 ratio means that to turn the wheel 1 time, the motors crank has to spin 27 times.

heathbar64 (author)2011-10-20

this seems a bit crude, but I like that you actually built this up yourself rather than just buy and install a bike motor kit like the other ibles.

tokymaru (author)2010-11-22

or you can, you know...pedal.

BIGHAIRYDUDE (author)2010-09-22

you need more than one drawing i mean really did you even build this?

nachosyumm (author)2010-08-16

For anyone actually considering on building a motorized bike, here are a few sources:

2 stroke (author)nachosyumm2010-09-17

the bike sprocket on the back will not work the gear ratio is too low the bike will not move and the cluctch wil burn out seize bigg sprocket 45 teeth and plus is recomended you need to go to and use their ratio calc or the eas cheap way is friction drive thats what i have on my chainsaw bike works flawlessly

ironsmiter (author)2010-08-14

25-49CC is the usual range for a road bicycle motorization kit.

If you go to make this, there are a few important facts to consider.

1) Make SURE you have a free-wheeling rear wheel. otherwise, bad things will happen to your legs :-)

2) seriously consider upgrading to disc brakes if you haven't already. Normal pincer type brakes will NOT be up to the task of stopping you.

3) Consider having a professional bike shop lace a special rear wheel for you. One with a standard gear hub on the normal side, and a granny gear on the other side(opposite your normal bike chain). That will let you run motor power, leg power, or both, AND stay within the motorized bicycle category(in the US anyhow). Anything without pedal power, or larger than 50cc motor, is considered a scooter here in the states. and requires an M class drivers license classification(also requiring 18 years of age in most states).

joshfreak=] (author)2010-08-14

yeah, i think so too

kelseymh (author)2010-08-13

If you've actually built this, you could greatly improve this instructable by providing actual pictures of your build, rather than just the same old drawing over and over. If it is just an idea you have, then you should say that up front, and make it clear that you have not actually built anything.

bombmaker2 (author)kelseymh2010-08-13

I agree.

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