BMW R27

The BMW R27 was a 247 cc shaft-driven single-cylinder motorcycle that BMW introduced in 1960, and BMW built 15,364 of them up to 1966. It was based largely on the R26, which had appeared in 1956 with an enclosed drive shaft, a rear swingarm and Earles front forks, but the R27 added rubber engine mounts and raised output to 18 hp (13 kW), the highest ever for a shaft-drive BMW single. Its 250 cc overhead valve vertical single was the only rubber-mounted thumper engine BMW ever produced and the company's last shaft drive single-cylinder machine. The crankshaft was laid out fore and aft so that the crank and the final shaft were in line and drive forces did not pass through 90-degree gears, and the triangulated Earles fork meant the front end rose slightly under hard braking instead of diving.