2012-08-24 17:05:23+0000
  • Make:
  • Sunbeam
  • Model:
  • S7
  • Year:
  • 1946

The Sunbeam S7 is a British made motorcycle, in production from 1946 to 1956. It has a parallel twin, four stroke 487 cc engine with a top speed of 70 mph (113 km/h).

The Sunbeam was designed by Erling Poppe basing it on the BMW R75 designs that was acquired by BSA at the end of World War II.This was his vision of what a perennial industry theme would look like, ‟the car on two wheels." Built in Redditch, the engine layout was an unusual in-line 500 cc twin which drove a shaft drive to the rear wheel. The early S7 was expensive and over engineered which is why it is now the most sought-after and commands a premium over the S7 De-Luxe and the S8, which were produced with fewer features to reduce costs, while retaining many of the innovative parts of the early Sunbeam and updating some ideas.

Three models were produced, the S7, the S7 "de luxe" and the S8. The original S7 (which was known as the "Tourer") had 2,104 produced between 1946 to 1948. It was expensive and did not sell well. In 1949 the S7 was updated to become the S7 de-luxe and 5,554 were produced and the S8 had 8,530 produced.

The S7 had the comfort of a fully sprung frame (most prewar machines had only front suspension), large soft tires, and a stylized engine. With its roots in a 1932 BSA project called "line-ahead twin," the 1946-47, S7 was a radical conception, with its 70-x-64-mm single-overhead-cam engine built in unit with a four-speed gearbox and mounted in rubber to isolate the rider from its considerable vibration. Unlike the Speed Twin and its clones, the S7 carried its crankshaft longitudinally, as an automobile does. The chassis incorporated the best suspension concepts developed in prewar racing, a telefork with hydraulic damping, and plunger rear suspension.

Although 16,000 of these machines were sold through 1956, British postwar motorists turned to, once it became available, the lower-priced motorcar. Despite its postwar financial crisis and the rationing of food and fuel, England had big plans for its motorcycle production. Innovation was certainly plentiful, but scarce money and a worn-out production system proved fatal. Ultimately, it wasn't enough. The death of the BSA motorcycle industry has been blamed on Japanese competition.

British design was strongest during its last days. The Sunbeam is a prime example of this; the original S7 Tourer is now highly collected. A fine example can be seen in person at the Barber Village Motorsports Museum in Birmingham, Alabama.

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