BMW entered the market in 1938 with the RS51 (Rensport, 17 built), a very fast motorcycle that was for sale to the public in a toned down version the R51. Henne had achieved very many successes with this motorcycle and made and sold many parts to rebuild and spruce up the R51 for racing.

After the war the 2 factories in Munich and Eisenach were destroyed and Germany was not allowed to build heavy motorcycles because otherwise they could possibly rebuild the army. Then mostly 1 cylinders were built. This was so until 1951 when they were allowed to build heavier motorcycles again. BMW then immediately presented the R51/2. This was no longer a sport motorcycle but a touring motorcycle. Because no other (outside the factory racers) sport motorcycles were built you could buy a conversion kit from Henne to build your own fast sport bike with R51RS parts.

All these (expensive) racing parts are also in this motorcycle. this one has the racing tank, Henne seat, gearbox without air filter because there are 2 carburetors now, racing gearbox with racing ratios (very long 1st), High compression engine, RS camshafts, reinforced frame,... This motorcycle is such a post-war conversion of a 1939 RS model to participate in racing.

This is a very fast racer with which many classic races have already been run.