Hi!! I motorized last summer using my 15 year old mountain bike I had in the garage and a 4 stroke eBay kit with the JL Hoot gearbox and the Huasheng engine. Did a lot of adjusting, problem solving, and head scratching. No big mistakes, so I'm making progress. Used to do this with my cars, but they are getting to complicated to mess with. I think an average dude like me likes to be able to play with his toys. Long live "Motorbicycling.com"!