need help and advice asap.

ok so i have a doodle bug with a predator 212 with pipe and muffler, air filter, and 140 e tube and 36 jet. anyways it is hitting 40mph. but i want to change the back sprocket to a smaller one to give it more top end speed. because right now it has a 12 tooth clutch with a 70 tooth back sprocket. it has way to much torque if you ask me and i want a little torque and alot of speed. so i was thinking of getting a 45 tooth back sprocket. any ideas on that? is that the size i should get? how much of a difference would that make? and if so where could i find a sprocket like this. ive been looking and i havent found anything. i have a #35 chain and also i bypassed the governor.


Active Member
First thing is with no governer then you need a billet rod and flywheel. Second a 45t is gonna be to small, a 60t will probably get you where you want to be. OldMiniBikes warehouse sells an adapter and split sprockets for the doodlebug. There is a speed calculator in the engine modification section section that you can play with to figure out top speed with different gearing.