The BMW That Never Was: The R73

Even with all BMW models since 1923 being referred to numerically like the R32 and the R90S, there is one moniker you won’t find in BMW history books, the R73.

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by Somer Hooker

BMW motorcycle nomenclature has always been about “numbers.”

Since 1923, all models have been referred to numerically, such as R32, R69S, R90S, and R1200GS, with the “R” standing for rad or cycle in German. However, there is one moniker you won’t find in BMW history books, the R73.

black and white photo of a motorcycle with sidecar drifting around the corner of a…

In 1944 as the Wehrmacht troops began retreating from Paris, they left behind a motorcycle repair depot with a cache of replacement engines and parts for BMW motorcycles. Amongst them were approximately 80 unused 750cc R75M engines. Recognizing an opportunity, the enterprising French soon set up a corporation and began manufacturing motorcycles under the name CMR, short for Centre de Montage de Reparation. Having little use for lugging a heavy sidecar, the French adapted the 750cc engine for use in the lighter, civilian R71 frame. Once the supply of surplus BMW frames was exhausted, CMR produced a close copy with the slight difference of round instead of oval frame tubing. These machines would later become known as the R73, a mix between R71 and R75 (71+75/2=73). The moniker is akin to Norvin for a Norton-Vincent conversion or Triton for a Triumph-Norton conversion. The popular BMW plunger frame design was subsequently copied by numerous manufacturers around the world. In Russia, Ural produced a near-direct copy with their M72 motorbike. The Chinese Chang Jiang is a knock off as well. Indeed, many of the parts interchange. It is common for bikes that saw postwar service behind the iron curtain to be a mix of parts.

front view of a black and gray motorcycle

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