I have a 1950's model Rollfast bicycle that I put a 1957 David Bradley ug4 gear drive chainsaw motor on. Its a 77cc 4hp motor with a reed valve carburetor and will do 40+ mph(way to fast lol) custom kickstand and motor mounts. it has 17 inch rims and tires from a Puch moped. It is my second motorized bike build. I hope you all enjoy the enclosed pics and I would appreciate any feedback, thanks.