Sunbeam S7 500 (1946-56)

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The Sunbeam S7 500 motorcycle was produced between 1946-1956 with a total production of 7,658 units including the De Luxe models. It is powered by a 487cc parallel twin, SOHC engine with a maximum power output of 18.6 kW/ 25 hp at 5800 rpm. The engine has a compression ratio of 6.5:1 and is cooled by air/oil. Lubrication is provided by a wet sump and the starting system is kick-start only. The electrical system is a 6V unit. The bike is equipped with a single plate clutch and a 4-speed transmission with shaft final drive. The frame is a twin cradle steel design with telescopic front suspension and plunger spring-loaded saddle rear suspension. The front and rear brakes are both drum, leading shoe, with a diameter of 203mm or 8″. The wheels are 16″ with a front size of 4.50 x 16″ and a rear size of 4.75 x 16″. The bike has a wheelbase of 1400mm or 57″ and a dry weight of 195 kg or 430 lbs. Its top speed is 121 km/h or 75 mph.

Technical specifications:

Make Model: Sunbeam S7 500, S7 500 De Luxe

Year: 1946 – 56


Production: 7 658 units (inc. De Luxe models)
Engine: Parallel twin, SOHC
Capacity: 487 cc / 29.7 cu in
Bore x Stroke: 70 x 63.5 mm
Compression Ratio: 6.5:1
Cooling System: Air/Oil cooled
Lubrication: Wet sump
Starting: Kick
Electrical system: 6V
Max Power: 18.6 kW / 25 hp @ 5800 rpm
Clutch: Single plate, dry
Transmission: 4-Speed
Final Drive: Shaft
Frame: Twin cradle, steel
Front Suspension: Telescopic, one way damped

Rear Suspension: Plunger, spring loaded saddle
Front Brakes: Drum, leading shoe, 203 mm / 8″
Rear Brakes: Drum, leading shoe, 203 mm / 8″
Wheel, Front: 4.50 x 16″
Wheel, Rear: 4.75 x 16″
Wheelbase: 1400 mm / 57″
Dry Weight: 195 kg / 430 lbs
Top Speed: 121 km/h / 75 mph
Source: Sump Publishing

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