If you dont have a #41 heavy duty roller chain on your bike. I highly recommend one! I was using the chain that came with the kit and it actually broke in 3 places. The guys on this forum recommended the #41 chain. Besides it just looking bad @ss, I don't have to worry about this thing breaking. Also, the motor seems to run better with it on there. I was skeptical that it would fit though. I did purchase the heavy duty chain that Kings Motor Bike sells last year. That chain fit around the rear sproket, but wouldn't fit around the front motor sproket. But the #41 fits just fine. I have the Grubee 48cc motor.