1949 Imme R100, Its rear wheel is supported on one side with the exhaust pipe, the rear wheel and engine move as a unit! Also, check out that single-sided front “fork”.

Slide commented:
built by a guy named Riedel, a former engineer at Messerschmitt. *Imme*nstadt was his home town.

 It was made mainly by airplane parts: All tubes came from the 109´s airframe and the engine was a starter from a bomber.

The lower tube is exhaust and frame at the same time and carries engine and rear wheel. All in one part.

http://goodsparkgarage.com/moto-museum-st-louis/#more-9725