c.1937 BMW 494cc R5
Frame no. 502179
Engine no. 504054
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. Launched in 1923, the first motorcycle to be sold as a BMW - the R32 - featured a 494cc, 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.
An important step forward in the development of BMW's long-running flat-twin occurred in 1936 with the introduction of the 494cc R5. Prior to that the BMW engine had been recognisably related to the first of its type, the 1923 R32, and like those of its (494cc) predecessors, the R5's engine dimensions were 'square' at 68x68mm bore/stroke. However, the overhead-valve R5 engine broke new ground by adopting two chain-driven camshafts, a move that permitted shorter pushrods and higher revs. Maximum power increased to 24bhp at 5,800rpm while the top speed was an impressive 87mph (140km/h).
This R5 was acquired in the mid-1970s as a partially completed restoration project by the current vendor's late father and finished over the next couple of years. Started and run on a few occasions, the last being in 1978, the machine has been kept in dry storage ever since and will require re-commissioning before further use. There are no documents with this Lot, which is sold strictly as viewed. It should be noted that the engine is that of an R51, the R5's replacement that differed mainly by virtue of its plunger rear suspension.