Built by Maschinenfabrik Stein AG, Frankfurt/Main, 1922-1925.
If a two-stroke was described has having eight ports and a rotary inlet, it would not sound terribly antique. That was the 198cc engine which powered the Dolf! Sports and touring models were built with chain drive.
The Dolf first raced at the Opel track in 1922. It won, and for the next few years it was top of the class.
Source: Tragatsch p118, et al.
If you have a query or information about these German motorcycles please contact us