Positioned in BSA's sport motorcycle lineup, the 1971 BSA B50SS features a 499 cc (30.5 cu in) air-cooled single cylinder, four-stroke configuration. In factory specification, peak output is rated at 33.5 HP (24.5 kW) at 6,200 rpm while maximum torque reaches 37.9 Nm (28 lb-ft) at 5,000 rpm, transferring power to the rear wheel through chain final drive. With a specific output of 67.1 HP per liter and a 1,200 rpm working window between peak torque (5,000 rpm) and peak power (6,200 rpm), the engine character is indicating a tractable, stress-free state of tune focused on everyday usability and broad torque delivery.
On the scales, the B50SS measures 140.6 kg (310 lbs) dry, translating to a power-to-weight ratio of 0.24 HP/kg (4.2 kg per horsepower). Rider ergonomics and chassis geometry center around a 813 mm (32 in) seat height — offering a neutral standover height that accommodates most average-inseam riders without sacrificing cornering clearance, combined with a 1,372 mm (54 in) wheelbase engineered for quick, flickable steering geometry.
Specific Output
67.1 HP/L
Power-to-Weight
0.24 HP/kg (4.2 kg/HP)
Power Band Window
5,000–6,200 rpm
Standover Height
813 mm (32 in)
Engine
Displacement499.0 ccm (30.45 cubic inches)
Engine TypeSingle cylinder, four-stroke
Power33.5 HP (24.5 kW)) @ 6200 RPM
Torque37.9 Nm (3.9 kgf-m or 28.0 ft.lbs) @ 5000 RPM
Compression10.0:1
Bore x Stroke84.0 x 90.0 mm (3.3 x 3.5 inches)
Fuel SystemCarburettor
Fuel ControlOverhead Valves (OHV)
IgnitionLucas RM21
CoolingAir
Transmission
Final DriveChain (final drive)
ClutchWet, multiplate
Performance
Top Speed136.8 km/h (85.0 mph)
Chassis
Frame TypeWelded, with larger diameter Top Tube
Front SuspensionTelescopic
Rear SuspensionSwingarm , Dual Shocks
Wheelbase1372 mm (54.0 inches)
Ground Clearance191 mm (7.5 inches)
Wheels & Brakes
Front Tyre3.25-18
Rear Tyre3.25-18
Front BrakesExpanding brake (drum brake)
Rear BrakesExpanding brake (drum brake)
Dimensions & Weight
Dry Weight140.6 kg (310.0 pounds)
Power/Weight0.2385 HP/kg
Seat Height813 mm (32.0 inches) If adjustable, lowest setting.
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Torque
Torque is useful for judging real-world pull, especially for touring, commuting and loaded riding.
Seat Height
Check the seat height against your inseam and riding posture before choosing a motorcycle.
Weight
Compare weight carefully because it affects low-speed handling, parking and confidence.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
