We have seen examples earlier that some people are able to fit Honda 4-stroke moped engines on non-Honda frames and here is another example. We will call it the NSU PF50.
NSU Motorenwerke AG, normally just NSU, was a German manufacturer of automobiles, motorcycles and pedal cycles, founded in 1873. It was acquired by Volkswagen Group in 1969. VW merged the company with Auto Union, to eventually evolve into Audi as it is known today. Source: Wikipedia
Found by Scrambler.