I built a 26" bike with a 44 tooth sprocket and a 60cc motor. I rode it side by side with my motorcycle and it did 40mph but was reving what I thought was insanely high. Now I'm building a bike with 20" tire and wondered how small a sprocket I should go with to match or better the the ride. Not to go faster but to get the rpms down. This would be harder on the clutch but better on the motor right? Now that I'm on the subject, the clutches are replaceable right? Thanks guys!