Home Technology 1950 Sunbeam S7 487cc Two Cylinder

1950 Sunbeam S7 487cc Two Cylinder


The Sunbeam S7 and S8 are British motorcycles designed by Erling Poppe with styling loosely based on the BMW R75 designs that were acquired as war reparations by BSA full rights to the Sunbeam brand had been acquired from AMC in 1943.Designed in wartime, the Sunbeam inline twin was introduced in 1947.

source.image: classic-motorcycle.com

A luxury tourer inspired by the pre-war BMW, it was of advanced specification with overhead-camshaft engine, shaft drive, and plunger rear suspension. The clutch housing and four-speed gearbox bolted directly to the back of the engine, which was rubber mounted in the duplex loop frame, an innovation that required a flexible joint in the exhaust system ahead of the silencer.

The first S7 version was equipped with balloon tyres, a feature not carried over to the more conventional S8 introduced in 1949. Never as popular as BSA’s more performance orientated models, the gentlemanly S7 and S8 remained in production until 1957.This S7 is ready for the road and runs smooth.


The original model was the S7 (the “Tourer”) (2,104 produced from 1946 to 1948), in 1949 the S7 was updated to become the S7 de luxe (5,554 produced) and the S8 (8,530 produced). Both had new cylinder linings, redesigned frames and increased oil capacity. The lighter S8 was sold as a “sportier” model with a top speed of 85 mph (137 km/h). It also had new (BSA) forks, a cast aluminium silencer and chromed wheels (with narrower tyres to replace the ‘balloon’ tyres which had led to uncertain handling at speed).