I have a standard 20" BMX bike that I'd like to put a motor on. I don't have much money, no welder or much knowledge on how exactly to do this. I was thinking of using a weed wacker motor if I can find one at a garage sale or something. I just want a little project...something fun. I want to be able to pedal the bike too though. Not sure where to start but, if someone could point me in the right direction, that'd be great. Thanks.