Built over four years, the R51/3 was introduced in 1951. It was one of the first bikes BMW released after they were allowed to start creating motorcycles post WWII, so they took one of their pre-war designs and evolved it to prevent having to start from scratch.
The 494cc four-stroke twin yielded 24 horsepower, good enough to move the 419 pound bike up to 87 miles per hour. This numbers-matching example (VIN: 527593) has been restored and is claimed to run strong.
Find this R51/3 for sale in Dresden, New York with bidding up to $11,100 and the reserve met (so this will sell)