Ok here is what i did and the problem i ended up with... this is the bike i started with for $10.... then i painted it black and cut and extended the front forks 8" and put a smaller wheel in the front.... then i took the 4hp engine off a old snowblower that i had and tucked it in the frame and bolted it down.... then since the direction of the crank pulley was the opposite of where the sproket was on the bike i had to build a jackshaft to bring the power to the other side. AND the reason the clutch is not on the engine is because i didnt have access to one with a 1" shaft size like this engine has. so i have a 3" pulley on the crankshaft of the engine, a 2" pulley (not pictured) on the crank shaft side of the jackshaft, the centrifugal clutch on the drive side of the bike and a chain to the original back tire sprocket which is a 20T. and since the sproket on the clutch was a different size chain i welded a 20T sprocket to the one on the clutch. (all i had).... now for the ISSUE... im sure you veterans of the motorized bike world here will see issues all over this thing (my first attempt at homemade motor bicycle) the problem is that the clutch engages now but the bike doesnt want to move with me on it at all. if i lift the rear up the tire will go super fast when given throttle. the clutch just smokes if i keep the throttle on too long when im sitting on it. im thinking it has to do with the tiny rear tire sprocket, can anyone tell me what they think is wrong... id rather have a good power to speed ratio. please help!!!