BSA A 50 Royal Star

BSA A 50 Royal Star

year icon
Model year
1970
make icon
Make
BSA
power icon
Engine Power
32.77 HP (24.1 kW) @ 6500 rpm
Speed icon
Top Speed
90.1 mph

Technical Specifications

Engine and transmission

  • Engine type:
    2 cylinders, 4-stroke, Inline
  • Displacement:
    498 cc (30.43 cubic inches)
  • Bore × stroke:
    2.58 inch × 2.91 inch (undersquare - longstroke)
  • Cooling system:
    Air cooled
  • Power:
    32.77 HP (24.1 kW) @ 6500 rpm
  • Throttle:
    Cable operated
  • Valve train:
    OHV, variable
  • Valves per cylinder:
    2
  • Sparks per cylinder:
    1
  • Fuel supply system:
    Carburetor
  • Ignition type:
    mechanically timed
  • Compression:
    9:1
  • Engine mounting:
    Transverse
  • Lubrication system:
    Wet sump
  • Gear box:
    Manual 4-speed
  • Clutch:
    Wet, multiple discs, cable operated
  • Final drive:
    Chain
  • Spark plug pipe type:
    NGK
  • Motor oil:
    Mineral, 10W/40
  • Starter:
    Kick-starter

Dimensions

  • Curb weight:
    425.5 lbs
  • Dry weight:
    392.4 lbs

Chassis and suspension

  • Front
    Suspension:
    Cartridge
    Brake:
    Single Drum
    Tire:
    83 / 100 R19
    Tire pressure:
    0.12 PSI
  • Rear
    Suspension:
    twin shock, Swingarm
    Brake:
    Drum
    Tire:
    89 / 100 R19
    Tire pressure:
    0.14 PSI
  • Frame type:
    iron, Single cradle frame

Other

  • ABS available:
    No
  • Power-to-weight ratio:
    0.12 KW/lbs (8.01 lbs/HP)
  • Acceleration (0-60 mph):
    7.8 sec
  • Top speed:
    90.1 mph
  • Fuel capacity:
    3.96 gals
  • Number of riders:
    2 persons

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