BMW 1928 R 63 734cc OHV transverse twin frame # 23169 engine # 75157
In 1928 BMW presented two new 500s, the side valve R 52 and the overhead valve R 57. The company also provided engines in the 750cc class with the same cycle parts: the 745cc side valve model R 62 with bore x stroke of 78 mm and the 734cc ohv R 63 with bore x stroke of 83×68 mm. The R63 was with its 24 HP a spirited performer on the road but it was also raced by the works alongside its 500cc stablemates. Like the latter, it pioneered the factory’s use of supercharging. For the standard R 63 a relatively modest 120 km maximum was claimed. But a modified version provided BMW with the means of securing its first motorcycle land speed record; Ernst Henne achieved a maximum of 216,8 km on a ‘blown’ example in 1929. The R 63 had a bore/stroke ratio of 1.22:1 and the relatively large piston area was an excellent basis for further development: in 1935 Henne reached 256.1 km on the blown 750 cc record-breaker in its final highly tuned and elegantly streamlined form.
The arrival of the fashionable ‘saddle’ fuel tank at the end of the 1920s meant that BMW’s distinctive wedge-shaped tank had to go. The resulting wholesale revision of the design undertaken for 1929 would later confer iconic status on these early BMWs. The R 63 is highly sought after as the first ohv BMW in the 750 cc class. Its high price meant that only the happy few could afford such a machine; less than a thousand were made in 1928-1929. She delivers her 24 HP @ 4000 rpm. Accessories include a German-made Hasag search light, a steering damper, a leather tool bag on the rear carrier and a “Mobiloil” triangular oil can in holder. This machine is a good runner; she comes with Bosch lighting and has been restored a number of years ago.