Depends on what you want. Electric? Cheap 2 stroke HT? Other 2 stroke? High quality 2 stroke like a Mitsu or Tanaka? 4 stroke? How big? Do you need to stay under 50cc to be legal? What type of engine mount, in frame or rack mount? Daily ride, like a commuter, or recreational toy? Do you ride where it is flat, or do you have steep hills where you are? Do you already have a mount kit in mind? Lots of questions.
