I need some info on this topic. I just sent my motor to a guy that is going to rebuild it. He said by tues or wed he will let me know the parts I need to replace. What I wanna know is if I can put a bigger piston, like to make a 300cc engine, or what not. I did see bigger piston kits in the Dennis Kirk Catolog, but I would like to know what else I need. The guy I dropped it off to is on Vacation so I couldn't ask him. Please let me know. THANKS