Windhoff Motorradenbau GmbH built motorcycles in Berlin, Germany, from 1924-1933. The factory was located at Bülowstrasse 106, Berlin W57, under the direction of factory owner Hans Windhoff. Windhoff initially produced radiators for cars, trucks, and aircraft, setting up a factory with his brother Fritz in Rheine in 1902, then on his own in Berlin from 1907-24. In 1924 he entered the burgeoning German motorcycle market with a water-cooled two-stroke of 125cc. The engine was built under license from a design by Hugo Ruppe, whose ladepumpe (an extra piston used as a supercharger to compress the fuel/air mix) design was used most successfully by DKW in their Grand Prix racers. Windhoff had much racing success with these small two-strokes, although an experiment with enlarged two-stroke racers