Sunbeam 1928  Longstroke engine 492cc sv 3404



Sunbeam 1928  “Longstroke”  492 cc side valve engine # J2170

The famous 77 x 105.5  Longstroke engine, in its various guises, was in production for 17 years – the longest of any Sunbeam motorcycle engine. It made its debut in the 1921 French Grand Prix and for a number of years was almost unbeatable in the various speed events. This particular engine was fitted to the Model 5 Light Tourist and the Model 6 Longstroke. 1928 was the first year Sunbeam employed a built-in oil pump. The engine we present here is turning but we have no details about its internal condition.