I restored two VeloSolex mopeds. Initially I put new Hongdu replica engines on, but I found them to be noisy and under-powered. So I took the plunge and went electric. I found some great 36v motors on ebay, and put two on the front wheel of each bike (of course one runs in reverse.) I demolished one of the engines to get the friction roller out, and the other roller is custom (steel with a bunch of very rough welding all over the surface.)
Dan Kastner:
What is the motor called? I will add it to the list.