This gorgeous flat-tank BMW is only the factory’s second-generation model, a successor to its original R32 of 1923 and a much better machine by every standard. BMW was established as an aircraft engine manufacturer in 1917 to supply Germany’s military during World War I. The Treaty of Versailles ended all armaments manufacture, so BMW turned to building motorcycle engines in 1920.
The flat-twin engine design by Max Friz followed in the footsteps of Douglas and ABC in the UK, which had the advantage of perfect primary balance and easy air cooling when turned transverse to the frame. BMW supplied flat-twins to manufacturers like Victoria for a few years before taking up whole motorcycle production in 1923. BMW’s first production motorcycle, the 1923 R32, was a simple machine but a revolutionary design. While flat-twin engines had been built before, BMW’s design included a shaft final drive, which became forever associated with the brand. BMW rapidly developed its flat twins from that first R32, updating the motor with detachable aluminum cylinder heads in 1926 for the R42. The R42 was significantly more powerful (12 HP versus 8.5 HP) and handled better as the engine was placed lower and further back and the frame was strengthened with straighter tubes. The brakes were improved with a drum up front and the rear clamping on a small drum on the actual driveshaft. The 3-speed gearbox was still bolted to the motor, and the kickstarter acted through a bevel gear so that it arched in line with the chassis rather than across the frame (as with all BMWs after 1928). The R42’s looks were modernized with slimmer fenders, and electric Bosch lighting and a horn were optional. The R42 weighed only 277 pounds, and it’s a charming machine to ride. This beautiful, fully restored 1927 BMW R42 is a very rare machine from the series’ short run between 1926-28. Production was very low in this era as BMW found its commercial footing and the company’s reputation grew through competition and quality construction. This is a very correct restoration and among the most coveted model of early BMWs as it is so rare and a very competent motorcycle even today.