The Sunbeam S8 was a motorcycle produced from 1949 to 1956. Around 8,530 units were produced during its run. The engine was a 487 cc parallel twin with SOHC, capable of producing a maximum power of 18.6 kW/25 hp at 6000 rpm. The compression ratio was 6.5:1, and the cooling system was air/oil cooled with lubrication via wet sump. The starting system was a kick-start and the electrical system was 6V. The clutch was a single plate, dry type, and the transmission had four speeds. The final drive was via shaft. The frame consisted of a twin cradle made of steel. The front suspension was telescopic with one-way damping while the rear suspension was plunger with a spring-loaded saddle. The front and rear brakes were drum, leading shoe type with a diameter of 203 mm or 8 inches. The front and rear wheels were 4.50 x 16 inches and 4.75 x 16 inches, respectively, while the front and rear tyres were 4JA x 16 inches and 43A x 16 inches, respectively. The wheelbase was around 1400 mm or 57 inches, and the dry weight was 187 kg or 413 lbs. The top speed was 121 km/h or 75 mph.
Technical specifications:
Make Model: Sunbeam S8 500
| Year | 1949 – 56 |
|---|---|
| Production | 8 530 units |
| 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 @ 6000 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″ |
| Tyres, Front | 4JA x 16″ |
| Tyres, Rear | 43A x 16″ |
| Wheelbase | 1400 mm / 57″ |
| Dry Weight | 187 kg / 413 lbs |
| Top Speed | 121 km/h / 75 mph |
| Source | Sump Publishing |
