| MODEL | BSA B40 350 MILITARY 1967 - 1970 |
| Year | 1967 - 1970 |
| Engine Type | Four-stroke, single cylinder, OHV, dry sump |
| Displacement / Capacity | 343 cc / 20.9 cu in |
| Bore X Stroke | 79 x 70 mm |
| Compression Ratio | 7.0:1 |
| Cooling System | Air |
| Max Power | 14.7 kW / 20 hp @ 7000 rpm |
| Max Torque | — |
| Ignition | Magneto, 12V 8Ah battery |
| Induction | Amal 396, 397 or 398 carburettor |
| Start System | Kick |
| TRANSMISSION SPECS | |
| Lubrication | Dry sump, 2.8 L / 5.9 US pints |
| Gear Box | 4-speed |
| Clutch | Multi-plate, cork insert |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | Welded tubular steel, full cradle |
| Front Suspension | Telescopic forks, coil springs, hydraulic damping |
| Rear Suspension | Swinging arm, coil-sprung hydraulic units |
| Front Brakes | Drum, 1.125 x 7 in |
| Rear Brakes | Drum, 1.125 x 7 in |
| DIMENSION SPECS | |
| Overall Length | 2100 mm / 82.6 in |
| Overall Width | 750 mm / 29.5 in |
| Overall Height | 1080 mm / 42.5 in |
| Seat Height | 813 mm / 32 in |
| Wheelbase | 1360 mm / 53.5 in |
| Ground Clearance | 159 mm / 6.3 in |
| Dry Weight | — |
| Wet Weight | 165 kg / 364 lb |
| WHEEL SPECS | |
| Front Tyre | 3.00 x 18 trials universal |
| Rear Tyre | 3.50 x 18 trials universal |
| FUEL SYSTEM | |
| Fuel Capacity | 15.9 Litres / 4.2 US gal |
| Fuel Consumption | 4.5 L/100 km / 52.2 US mpg |
| Top Speed | — |
The B40 was a 343 cc overhead-valve single that BSA offered as a light road bike and, in this form, as a British Army machine for dispatch and convoy work. The military version had a welded frame with pannier fittings, a more robust finish and modest power, trading speed for reliability. It was mostly a road machine and was not much good off the tarmac.
