In 1925 BMW entered the world of the single-cylinder motorcycle, with the aim of producing significant quantities for a market that seemed more popular and affordable than that of the large double-cylinder motorbikes with twin horizontal cylinders (Flat Twin), considered to be up-market and expensive. In fact, a single-cylinder machine was not as good as a double-cylinder one. It was cheaper and simpler, but there was a market of people who would rather have something imperfect than nothing at all.

 In1960 production of the new single-cylinder-27 began, drawing on the experience of swing-arm "Earles" forks mounted on the double-cylinders. But there was one important difference: the double-cylinder engines did not vibrate, but vibration-free single-cylinder engines were not feasible. The solution of the BMW engineers was to mount the engine and gearbox  in a flexible way, on rubber supports. On theR-27, the engine, gearbox and exhaust were all isolated from the chassis. No vibration or movement could pass from the engine to the chassis, thanks to generous rubber padding  support s, which had to be inspected every 16,000 kilometres.

This motorbike weighed 162 kilos and the chassis was strong enough for a 250 c.c. engine. All this resulted in a very special and sturdy machine, with all the air of steady solidity which has long formed part of the BMW character. But in 1960 a decline in demand for these motorcycles, and for the motorbike as a mode of transport, was already underway. After a production of 15,364 units in almost 8 years, the quietest, smoothest and most sophisticated single-cylinder motorbike of its time went out of production in 1967. The design of the R-27 was too expensive for this type of machine. The times were such that BMW even questioned whether it should continue to manufacture any kind of motorcycle.