I have one of those 4 stroke kits with the red plastic. stay away from these they are nothing but headaches. the engine burns oil like crazy, and the oil gets dirty real fast. the carb floods, its hard to start, and finally the clutch is made from **** rubber. and to top it off there are no parts available outside of grubee. I dare go into the quality of gearbox that we get? I will sell somebody my engine sans exhaust for 50 dollars. the biggest waste of money ever. I am going to design my own kit by contracting with american engine companies. i can do better than these hacks who are forcing garbage kits onto the market. You should not have to be held by the balls when you are trying to buy clutches or piston rings for your engine. You guys are plain crazy. I hope those who are considering buying a 4 stroke kit to keep thier money.