OK so I need some help on a first build. I want to know what motor kits to get. I don't have much funds right now so want to start with a 49/50cc 2 stroke kit but I want to upgrade to a inframe 4 stroke later on, so suggestions on both are needed. The two main things I'm looking for are price and reliability.I'm doing a mountain bike frame but haven't bought one yet so if the kit doesn't have clearance specs I would need that too. Also I'm doing a jack shaft so I guess that would effect clearance issues. Any help would be greatly appreciated!
--also slightly larger motor sizes would be ok as long as johnny law can't tell just by lookin at it.