This is a 1928 Windhoff Four 746cc, a valuable and rare vintage motorcycle made by German company Windhoff. The bike, up for an auction on 29 Apr 2012 at Bonhams Stafford, has a current estimated sale price of £100,000-£130,000 or $160,000-$210,000 USD. At its day, Windhoff Four was one of the most technologically advanced, innovative, and impressive four cylinder motorcycles, introduced at the Berlin Show in 1927. This bike had three owners—the current owner bought it at a Bonhams Stafford sale in April 2008 and had the bike on display in his private museum.
Founded in 1880 by the Windhoff brothers, Windhoff was a German company based in Berlin. It was a successful manufacturer of radiators for aircraft and automobiles when it introduced its first motorcycle in 1924. The first Windhoff motorcycles, with models 500cc and bigger, featured a powerful and efficient water-cooled two-stroke engine that incorporated a pumping cylinder.
Windhoff Four was the company’s second line of motorcycles designed by Ing. Dauben, an auto engineer who later worked for Mercedes-Benz. Windhoff Four was smoothly styled—all oil lines were internal. The bike was famous for its smooth ride even at extremely low speeds. One of its innovative features was its oil cooled overhead-camshaft engine that was also part of the frame. The engine was an over-square design, 63x60mm bore/stroke with maximum output of 22bhp at 4,000rpm. Because of its advanced features, Windhoff Four was very expensive and didn’t sell well, especially since it was introduced during the economic depression in the 1930s.
After Windhoff Four, the company tried unsuccessfully to build and sell two-stroke lightweight bikes with Villiers engines built under licence. The last Windhoff motorcycles were built in 1933.