| MODEL | BSA A 1921 - 1924 |
| Year | 1921 - 1924 |
| Engine Type | Four stroke, V-twin, side valve |
| Displacement / Capacity | 770 cc / 50 cu in |
| Bore X Stroke | 76 x 85 mm |
| Compression Ratio | — |
| Cooling System | — |
| Max Power | 4.4 kW / 6 hp |
| Max Torque | — |
| Ignition | Magneto |
| Induction | — |
| Start System | Slip-on kick starter |
| TRANSMISSION SPECS | |
| Lubrication | Constant-loss oil pump with hand-operated pump |
| Gear Box | 3 Speed |
| Clutch | — |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | — |
| Front Suspension | Single spring girder fork |
| Rear Suspension | None, spring-loaded saddle |
| Front Brakes | — |
| Rear Brakes | — |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | — |
| Ground Clearance | — |
| Dry Weight | — |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | — |
| Rear Tyre | — |
| FUEL SYSTEM | |
| Fuel Capacity | — |
| Fuel Consumption | — |
| Top Speed | 88 km/h / 55 mph |
A post-World War I V-twin tourer built around the 770 cc side-valve engine, finished in green and cream with a black frame. BSA sold it on reliability and dealer support, and the same engine powered about 100 BSA three-wheeled taxi cabs.
