It seems like a lot of people are going for 49cc engines. I myself got a 66cc engine because I wanted more power and the price really wasn't much different. Is there some reason why more people go for the 49cc? The only explanation I can think of is legal issues(in my state by law you can't go above 49cc on a motorized bike), but all you have to do is lie that it's 49cc and nobody is ever going to verify it.