1939 BMW R51. The 494cc BMW R51/2 was the first postwar boxer engine motorcycle produced by BMW after World War II. Five thousand were manufactured from 1950 into 1951. It was preceded only by the single-cylinder, hard-tail 250cc R24 of 1948-195. An excellent example of this pre-war motorcycle with BMW Owners club letter confirming original frame and engine together with original handbook and
