1955 BSA B33

1955 BSA B33

standard50sUnited Kingdom

The 1955 1955 BSA B33 is a 499cc single-cylinder standard motorcycle that became one of BSA's most memorable motorcycles of the 1950s.

Specifications

Engine

Type
OHV single
Displacement
499 cc
Cylinders
1
Power
23 hp @ 5500 rpm
Torque
35.0 Nm
Compression
Bore × Stroke
85.0 × 88.0 mm
Cooling
Air-cooled
Fuel System
Amal carburetor

Chassis & Transmission

Frame
Steel single cradle
Front Suspension
Telescopic fork
Rear Suspension
Twin shock
Front Brake
Drum
Rear Brake
Drum
Front Tyre
Rear Tyre
Transmission
4-speed
Final Drive
Chain

Performance

Top Speed
130 km/h (81 mph)
¼ Mile

Dimensions & Weight

Dry Weight
170 kg (375 lbs)
Wet Weight
183 kg (403 lbs)
Seat Height
780 mm
Wheelbase
1370 mm
Ground Clearance
Fuel Capacity
14.0 L

History & Story

In 1955, BSA launched the 1955 BSA B33 — a standard motorcycle that would come to define an era of motorcycling. Hailing from United Kingdom, it combined United Kingdom engineering with standard motorcycle appeal.

At the heart of the 1955 BSA B33 sits a 499cc OHV single engine producing 23 horsepower at 5500 rpm. The single-cylinder powerplant features a single-cylinder layout with air-cooled cooling, fed by Amal carburetor. Power reaches the rear wheel through a 4-speed transmission and chain final drive.

The chassis employs a steel single cradle frame with telescopic fork up front and twin shock at the rear. Stopping power comes from drum front and drum rear brakes. Tipping the scales at 170 kg (375 lbs) dry, the 1955 BSA B33 offers a manageable riding experience with a 1370 mm wheelbase.

Performance-wise, the 1955 BSA B33 achieves a claimed top speed of 130 km/h (81 mph). With a fuel capacity of 14.0 liters, it offers reasonable range for standard motorcycle duties. The seat height of 780 mm makes it comfortable for most riders.

Known Issues

  • Oil leaks typical of British singles and twins
  • Lucas electrical components unreliable
  • Primary chain adjustment critical
  • Period-correct fasteners and hardware hard to find

Fun Facts

  • The 1955 BSA B33 was produced in BSA's United Kingdom facilities
  • The 1955 BSA B33 featured a steel single cradle frame typical of 1950s design philosophy

Collector Information

Parts Availability
Moderate
Collector Rating
5/10

Resources & Parts