Welcome to the adiction Rocket. I started with one, now I have five runners, two bikes in progress, four more engines laying around and one really shiney one in my living room. The fun I have found in having in having several bikes is trying diffrent engines, as you can see from my signature, I don't stick to one engine type. So far my favorite engine id the Grubee 48cc round head, it seems to have more power and is quieter than any of the other bikes I have. Yep I'm hooked hard...My name is Kelly and I'm a bikeoholic.