Sunbeam. The S7 de luxe. 1956. 500cc.

The Sunbeam S7 and S8 are british motorcycles designed by Erling Poppe with a style loosely based on the designs of BMW R75 that were acquired as war reparations by BSA (the full rights of the trademark Sunbeam had been acquired from AMC in 1943). Built in Redditch, the unusual design of the engine was similar to that of a car.

A motorcycle Sunbeam S7 slightly custom.

The engine was a twin OHC 500cc. vertical in-line mounted longitudinally based on an experimental design BSA 1932 (the Line-Ahead-Twin - LAT) with ignition coil and lubrication by wet sump, through a dry clutch, drove a shaft drive to the rear wheel. The inline engine made this technologically feasible: the twin-engine horizontally opposed ("flat") on BMW motorcycles had already used transmissions on the y-axis according to the system used by the Nimbus four-cylinder engine from 1918. The first S7 was expensive and it was too designed, by what is now the most sought-after and have a premium over the S7 De Luxe and the S8, which were produced with fewer features to reduce costs, while retaining many of the parts innovative Sunbeam early and refreshed some ideas.

There were three models, the S7, S7 "de luxe" and the S8. The three were very expensive with a yield modest that resulted in low sales. The original model was the S7 (the "Tourer") (2.104 produced between 1946 and 1948), in 1949 the S7 was updated to become the S7 deluxe (5.554 produced) and the S8 (8.530 produced). Both had coatings of cylinders new, scenes redesigned and increased oil capacity. The S8 lighter was sold as a model "more sporty" with a maximum speed of 85 mph (137 km / h). I also had forks new (BSA), a silencer of cast aluminum and chrome-clad wheels (with tires narrower to replace the tyres 'balloon' that had caused a handling uncertain at high speed). Planned models S9 and S10, but never made as BSA decided to concentrate on the twins more traditional. We also tested another model "sporty", but was never put into production. This had a compression ratio much higher with a design OHC different, but never sold, supposedly due to the system of front fork without damping affecting the handling. There was also evidence with a strict version for a model that is more economic, but this design was also abandoned.

The S7 original was produced in black. The S7 deluxe came in "Mist Green" or black and the S8 in "Silver Grey" or black. For export abroad BSA supplied by sunbeam in any color BSA.