| MODEL | BSA X35-1 1933 - 1936 |
| Year | 1933 - 1936 |
| Engine Type | Four stroke, single cylinder |
| Displacement / Capacity | 249 cc / 15.2 cu in |
| Bore X Stroke | — |
| Compression Ratio | — |
| Cooling System | Air cooled |
| Max Power | 1.8 kW / 2.49 hp |
| Max Torque | — |
| Ignition | — |
| Induction | — |
| Start System | Kick start |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | — |
| Clutch | — |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | — |
| Front Suspension | Coil springs with steering damper |
| 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 | — |
A basic 249 cc BSA single built as affordable everyday transport during and after the Depression, sitting just above the 150 cc lightweight in the mid-1930s range. Plain, reliable and cheap to run, it earned the nickname grey porridge. It was renamed B1 for 1936.
