c.1933 BMW R4 Vertical Single
Lot 41
c.1933 BMW 398cc R4 Frame no. P3747D Engine no. 89138
Sold for £4,370 (US$ 7,345) inc. premium
Lot Details
c.1933 BMW 398cc R4
Frame no. P3747D
Engine no. 89138
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 while featuring shaft drive like the larger models. However, by BMW's 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 valve gear 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. An older restoration, this R4 was purchased in 2006 and is offered with German certificate of origin.