I had a buddy who had a R-50, he would let me ride it once in awhile. Once you got use to the drive shaft, coming from a chain drive bike, it was quite a nice bike and very, very comfortable. He had megaphones on it and it sounded pretty good.
Was it something like these?
But I think I would have preferred this:
That blue and white thing is the one! Our's was orange, leaked exhaust smoke into the cab and had minimum brakeing capability which was alright because it also had minumum acceleration capability! I think the boss thought I'd like to run it because it was "like a motorcycle"... WRONG!
My '58 R-50 had reverse cone megs on it and really sounded good. My buddy also had the same model but it was a German domestic model w/kilometers on the speedo instead of MPH. Ridin' them 2 side by side was music to the ears!