Manufacturer: NSU Model: 501 OSL Production: 1935-1939* Displacement: 494cc Engine type: 4-stroke / OHV (It looks like an OHC, but it's not) Cylinders: 1 Power: 22hp Bore/stroke: 80x99mm Maximum speed: 130 km/h
In 1929 NSU lured Walter Moore away from Norton. Moore had designed Norton's famous OHC machine, the CS1, so the similarity between the German firm's machine and the cammy Norton is no coincidence. In 1932 NSU introduced the Moore-designed O series OHV singles, and these became the most popular NSU models during the mid-1930s.
The 501 OSL was very fast, equipped to a luxury standard for the day, and was regarded as the ideal sidecar machine.
Postwar, the NSU Konsul was based on the 351/501 series.
* Sources vary, some giving 1932 - 1939 but this probably includes earlier 494cc models.