So. for the most part noone here gives the tiniest shit about crappy bolt on bicycle engines because they really have almost nothing to do with mopeds.
call it elitist. those things suck, mopeds are rad.
For real though, the bolt on 110's barely put out 4hp? That's pathetic, you can get that out of a stock moped engine with a pipe. That and they're made out of crap parts crappy material and are about the least reliable boxes of junk you can imagine.
As far as these bumble bee ones, friction drive is pretty retarded. these are ACTUALLY weedwacker engines made to drive a bicycle.
Finally, they never sold them on bikes. Maybe the one you're looking at is made by someone else, and bumble bee was the nearest thing they could find. Maybe it was sold as a kit by a 3rd party, like a bike shop that assembled and sold complete bikes.
Last point. I like solexes. get one of those.