| MODEL | AJS S3 V-TWIN 1931 |
| Year | 1931 |
| Engine Type | V-twin, side valve |
| Displacement / Capacity | 500 cc |
| Bore X Stroke | — |
| Compression Ratio | — |
| Cooling System | — |
| Max Power | — |
| Max Torque | — |
| Ignition | — |
| Induction | — |
| Start System | — |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | — |
| Clutch | — |
| Final Drive | — |
| CHASSIS SPECS | |
| Frame | — |
| Front Suspension | — |
| Rear Suspension | — |
| 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 | — |
The S3 was a 500 cc side-valve V-twin from AJS's last independent year before the firm's 1931 collapse and takeover by Matchless. It was a small-capacity V-twin roadster in the range alongside the S2.
