BMW R 39

The BMW R 39 was the first single-cylinder motorcycle from BMW. Launched in 1925 and designed as a sporting 250 cc machine, it had an overhead-valve engine of about 6.5 horsepower, a tubular steel frame and a short trailing-link front fork, with shaft drive to the rear wheel. It was built in much the same way as the large twin R 37 shown alongside it, which made it costly to produce, and only 855 units were made at a price of 1870 Reichsmark. Josef Stelzer won the German road championship in the 250 cc class on an R 39 in its first production year. Production was stopped before the decade ended and BMW did not build another single until the R 2 of 1931.