Direct drive through a centrifugal clutch requires a small drive sprocket, a large rear sprocket, and a small tire size to get enough reduction to not burn it when you are starting out.

Are you doing a direct drive off of the driveshaft on the motor, or do you have some sort of transmission worked out?  If you're going for dead-simple a centrifugal clutch on the drive shaft would probably be just the thing.

i have an engine with a horizontal driveshaft, Briggs and stratton 135202, so im going to put a chain and sprocket on there, with a gear on the wheel, probably pulled from an old mountain bike