1934 BMW 400cc R4
Frame no. P30041
Engine no. 88466
Following the collapse of its aero engine business after WWI, BMW turned to other areas of manufacture, motorcycles among them. Its first two models, marketed as the Frink and Helios respectively, were failures, but a successful proprietary engine was supplied to other manufacturers, such as Victoria. Designed by Chief Engineer Max Friz and launched in 1923, the first motorcycle to be sold as a BMW - the R32 - featured a 493cc, twin-cylinder, sidevalve engine having horizontally opposed cylinders, and this flat twin layout would forever be associated with the marque. Setting a pattern that endures to this day, the first BMW motorcycle was relatively expensive but superbly engineered and constructed, while the quality of finish was of the highest order.
Recognising the need for a less expensive model to compliment its top-of-the-range twins, BMW introduced its first single-cylinder design the R39 in 1925. Powered by a 247cc overhead-valve engine, the R39 came with a three-speed gearbox and featured shaft drive like the larger models. However, by BMWs standards the R39 was not a great success, and this first single-cylinder model was discontinued at the end of 1926.
The early 1930s Depression brought with it the need for an even simpler, and cheaper, model to compete with the lightweight two-strokes mopping up the lucrative up-to-200cc market. BMW responded with another single the 192cc R2 which appeared early in 1931 and sold well despite the difficult trading conditions, as did the 398cc R4, a favourite with police forces and the German Army. Intended to bridge the gap between the budget R2 and the expensive twins, the R4 looked much like the former, whose channel-section steel frame and running gear it used almost unaltered. The overhead-valve engine featured enclosed valvegear and produced 12bhp, gaining an extra two horsepower in 1933 when the R4 was updated to Series II specification with revised styling and a four-speed gearbox. R3 (300cc) and R35 (350cc) singles appeared later in the 1930s, all enjoying the benefits of shaft drive like their larger siblings.
This restored R4 is offered from long-term ownership and comes with owners handbook (in German) and assorted copy technical literature.