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Lot 311: 1927 BMW 500cc R42

Sale of Collectors' Motorcycles, Bonhams & Butterfields (12 November 2005)

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 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. Before long BMW updated its original tourer, which in 1926 became the R42, gaining a redesigned and more powerful engine boasting detachable alloy cylinder heads and cooling fins set at 90 degrees to the cylinder axis. The engine was set further back in the duplex loop frame, which improved weight distribution and enabled straight front down-tubes to be used. The braking too came in for attention: the old block-and-pulley type rear brake being replaced by a drum on the driveshaft gripped by external contracting bands. Electric lighting was still regarded as an ‘extra’ and would not be standardised until 1928. R42 production lasted for just two years and today this rare vintage BMW is among the marque’s most desirable and sought after machines of the period.

Finished in BMW’s traditional black with white coachlining, this immaculate R42 is offered fresh from restoration by a BMW dealer.

Lot Details
Auction Sale of Collectors' Motorcycles
Bonhams & Butterfields, Petersen Museum, Los Angeles, CA
TypeMotorcycle
Lot Number311
Estimate$18000-$22000
Outcome NOT SOLD
Hammer Price-
Hammer Price (inc premium)-
Year1927
Condition rating
Registration number
Mileage-
Chassis number
Engine number40021
Engine capacity (cc)
Engine - cylinders
Number of doors