Gear ratio assistance- 2 stroke Briggs

Nashville Geoff

New Member
Jul 29, 2008
Here's where I'm at... I have a 2 stroke, 3hp Briggs from a snowblower, planning to fab a rack mount- Centrifugal clutch, 11 tooth, #35 chain, with a jackshaft going down to a #41 chain, 50 tooth, dual freewheel hub. The bike is a 26" Giant ATX,with a front suspension fork & linear Shimano brakes.
I do plan on modifying the engine, disable the governor, probably a Tillotson carb, and a spicier exhaust. I may even try to mount a fatty expansion chamber from a kx80 that I have, with a little porting, a bump to the compression. I'm really in the dark regarding the rpm range that this engine will best operate within.
SO... I've run some numbers on the ratio program. a 35-40 mph top end is the target, with good uphill torque. What gears would you suggest for the jackshaft sprockets? TIA, Nashville Geoff