Ok i just replaced my crank bearings and i have the following mods... ported cylinder, ported intake, shaved head, hp airfilter, ported banana pipe, petcock from a moped and a 36t sprocket on 26inch wheels. I run octane booster and b8hs plug gapped at .025 and with the carb tuned all i get is 30 mph from her. And theres this knocking at top end maybe this crank is a dud or the timing is off or is it possible for a banana pipes silencer cones to get plugged? Shoot some suggestions guy ill do anything. Btw theres no leaks.