Re: New, lostand confused
There were a lot of manufacturers of clip on engines in post 1939 Europe, even a compression ignition 18cc Lohmann that would run on most combustible liquids. Mostly badly, but it ran. Friction drive, chain drive, complete hub motor units. All sorts.
Honda, Bridgestone and Suzuki all started their motorcycle companies with auxiliary engines as well. Take a look down the forum at the European and American lightweight pictures, there was a huge range of stuff.