they sold them a couple of different ways one of which was called Bismark. the engine was an NSU but the bikes are not built by them. In fact NSU was long gone by the time that the bikes were introduced.
I am pretty sure I have the Mini bike guide issue with the test report and more info. I'm out of town for a few days though but will look when I get back.
some biker dude that was on here before had one and was gonna ride it to Sturgis from Kentucky or something, dunno if he made it
ut: