Part Four: World War II
The German Wehrmacht commissioned BMW to build its first version of the R75 in 1941. The R75 was built with a sidecar, a lockable differential to power the side-car wheel, and a machine gun mounted on the sidecar. The R75 performed equally well in the sands of the North African Desert and the snow of the Russian Front. Its boxer engine was exposed to cooling air and its enclosed shaft drive was impermeable to sand and grit. With four speeds, reverse gear and a two-ratio transfer box, a skilled rider could traverse the most difficult terrain.
Joseph Stalin ordered the Soviet Military to acquire five units of the 1938 BMW R71 motorcycle (which was discontinued in favor of the R75, above). The five motorcycles were purchased on the black-market in 1941 through Swedish intermediaries. The motorcycles were disassembled and reverse-engineered so that the Soviets could build their own replicas of the bikes at their factory in Irbit, The Urals. That factory is known today as Irbitskiy Mototsikletniy Zavod-Ural and today, they still build the replica of the German WWII motorcycle with sidecar. They are sold under the Ural name and are very popular as a basic, hard-working sidecar rig. With low gearing, drive to the sidecar wheel and reverse gear, they can go almost anywhere.
The United States Military commissioned Harley-Davidson to design a new motorcycle in 1942 for the war-effort in the North African Desert. Drawbacks to the conventional Harley-Davidson design are the in-line V-Twin cylinders, which cause the rear cylinder to run hotter than the front, and the oiled-drive chain which collects sand and grit and causes premature wear of the chain and sprockets. Harley-Davidson designed the XA750 with transverse opposed cylinder heads which stay cool in the heat and enclosed shaft-drive which was impermeable to sand and grit.
Fascinating Fact: Imitation is the sincerest form of flattery. Both the USA and the USSR, our ally at the time, imitated the BMW motorcycles for performance in the battlefields.Part Two: Early European and British Motorcycles
Part Three: The First American Motorcycles
Part Six: The Later 20th Century: The Baby Boomers Become Young Adults
Part Seven: The Super Seventies
Part Eight: The American & Italian Connection