I was thinking of getting a gas weed eater and try to put the engine from that on a kick scooter. Would the work? Or maybe even a fan motor, i am not sure. It sounds like a fun project! Your best bet would be to try and use the weed eater. The big issues to address are:
How to mount the motor in a way to get the flex shaft to the rear wheel and the throttle lever to the handle or maybe some how make it a foot actuated throttle?
How to couple the rotating head to the rear wheel?
In my book, as a mechanical engineer, those are pretty big challenges. It would be more cost effective to by an electric Razor for $100-$200. | 