BSA A50 Cyclone (1962-70)

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The BSA A50 Cyclone/Royal Star was a four-stroke, twin-cylinder motorcycle produced from 1962 to 1970. It had a capacity of 498cc and a compression ratio of 9.0:1. The engine was cooled by air and lubricated by dry sump, with a maximum power output of 24.3 kW / 33 hp. The ignition was via a coil with spark plug Champion N4, and it had a kick start. The motorcycle had a multi-plate clutch and a 4-speed transmission with a chain final drive. It had a tubular pipe frame, double cradle with swingarm, telescopic forks for front suspension and double coil over for rear suspension, drum brakes at both the front and rear, and steel wire spoke wheels. The front and rear tyres were 3.25 x 19 inches (ribbed) and 4.00 x 18 inches (K70), respectively. The motorcycle measured 2100mm (81in) in length, with a height of 1117mm (44in) (western)/ 1028mm (40.5in) (standard), and had a wheelbase of 1391mm (54.8in). With a dry weight of 141kg (311lbs) and wet weight of 177kg (391lbs), its fuel tank had a capacity of 18.2 L / 4.0 Imp gal / 7.57 L / 2 US gal.

Technical specifications:

Make Model: BSA A50 Cyclone/Royal Star

Year: 1962 – 70


Engine: Four stroke, twin cylinder
Capacity: 498 cc / 30.4 cub in.
Bore x Stroke: 65,5 x 74 mm
Cooling System: Air cooled
Compression Ratio: 9.0:1
Lubrication: Dry sump
Oil Capacity: 3 L / 6.3 US pints
Carburetors: Dual, 1 1/16 in carburetors
Exhaust: Twin, stainless steel
Ignition: Coil
Spark Plug: Champion N4, 0.025 in. gap
Starting: Kick start
Max Power: 24.3 kW / 33 hp @ 5800 rpm
Clutch: Multi-plate
Transmission: 4-Speed

Final Drive: Chain
Frame: Tubular pipe, welded, double cradle with swingarm
Front Suspension: Telescopic forks
Rear Suspension: Double coil over
Front Brakes: Drum, 8 in.
Rear Brakes: Drum, 7 in.
Wheels: Steel, wire spoke
Front Tyre: 3.25 x 19 in., ribbed
Rear Tyre: 4.00 x 18 in. K70
Dimensions: Length: 2100 mm / 81 in. Height: Western: 1117 mm / 44 in. / Standard: 1028 mm / 40.5 in
Wheelbase: 1391 mm / 54.8 in.
Seat Height: 840 mm / 33 in.
Dry Weight: 141 kg / 311 lbs
Wet Weight: 177 kg / 391 lbs (4 gal tank)
Fuel Capacity: 18.2 L / 4.0 Imp gal 7.57 L / 2 US gal

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