31cc ryobi bmx, chain drive

hey, im thirteen and have been building things for as long as i can remember, this time i wanted to build a motorised bike, i was originaly going to use a homelite chainsaw but when i couldnt get it to start up after a rebuild i knew i was time to get a new engine, i went trashpicking and found a 31cc ryobi lawn hornet whipper snipper that had a clutch on it, i recently bought a bunch of clutches so if it wares out i can just pop another one on. the drive shaft setup is based around a 17.5 to 1 gear ratio and does the job perfectly, it doesnt bogg out and the clutch engages at a resionable time, on the engine there is a 11 tooth that goes to a 35 tooth that comes across the jacksaft to another 11 tooth to a 72 tooth go kart sprocket on the back wheel, i highly recommend using a 17.5 to 1 gear ratio for any small engine like this because it has a good all round torque and speed range, it will do 45kmh easily on flat ground and can get up most hills.

this was a great project to do and was very rewarding at the end of it, the bike is fuel efficient , fast and fun!

if you want to see this thing riding, go to youtube and search "Cchange4us", click on my channel and follow your instinct

diceman2004 said:

Thats pretty cool , i checked out the video , seems to run pretty good .
I like the way the motor fits nicely into that small space in the frame .
It would be nice if you could get the pedals back on , but it doesn,t look like thers much room left on the right side . Nice job with the chain drive .

Click to expand...

thanks, pedals were something i wanted to have just incase it broke down but this would mean i would have to have the sprocket on the other side of the rim so whenever the wheel moves the system momes and i didnt really want that

hey, thanks for your comment, a 66cc 4 stroke would be awsome, i dont recommend doing what i did with the jackshaft though, try a gear box of a scooter, unless you do this to a exeption quality (wich i didnt) you should go with a gear box then to a chain down the back