Do you have a question about the BSA B31 and is the answer not in the manual?
Key specifications and data for different motorcycle models.
Explains handlebar, foot, and general controls for riding.
Guidance on starting the engine and basic driving operations.
Instructions for breaking in a new engine and its lubrication system.
Routine service tasks at weekly, 1,000, and 2,000 mile intervals.
Procedures for wheel, fork, and steering head adjustments.
Adjusting ignition timing and valve clearances.
Adjusting clutch, chains, and brake systems for optimal performance.
Carburettor adjustment, plug maintenance, and air cleaner cleaning.
Procedures for cylinder head removal, valve, piston, and ring maintenance.
Adjusting suspension and specific instructions for competition/Gold Star models.
Care and servicing for battery, dynamo, and magneto.
Headlamp adjustments, bulb replacement, and wiring schematics.
| Engine Type | Single-cylinder, four-stroke |
|---|---|
| Displacement | 348 cc |
| Bore x Stroke | 71 mm x 88 mm |
| Transmission | 4-speed manual |
| Front Suspension | Telescopic forks |
| Brakes | Drum brakes front and rear |
| Ignition | Magneto |
| Compression Ratio | 6.5:1 |
| Power Output | 17 hp @ 5, 500 rpm |
| Fuel System | Amal Carburettor |
| Wheelbase | 54 inches |
| Top Speed | 75 mph |
| Fuel Capacity | 3.5 gallons (13.2 liters) |











