English Sunbeam 4HP 550cc model with belt drive. During World War I, many Sunbeams were delivered to Russia and other countries, but the largest customer was the British Royal Naval Air Service, the predecessor of the British Air Force. These were all 500cc with chain drive. France ordered 1,000 motorcycles, but with a 550cc engine and belt drive. This is now a very rare sight. Meanwhile, there are 9 of these motorcycles registered with the Marston Sunbeam Register... sorry, 10 including this one, because until now it was unknown as it had been in a private collection in France for many years. The motorcycle is an old restoration that could use some attention. The engine and gearbox have been overhauled and it starts and runs well. This motorcycle has the lowest known engine number. Production started in 1916 and continued until 1918. You can also see the letters GS, which stands for Generale Service, the French term for military service.