| General |
| Comments | - | Aluminium engine sump guard, high front mudguard, headlight grill, aluminium handlebar cross-strut, front stem protectors, dedicated logo |
| Year | 1957 - 66 | - |
| Model | Model 31 650 | - |
| Colours | - | Wild green |
| Make Model | AJS Model 31 650 | - |
| Dimensions |
| Seat Height | - | 790 mm / 31.1 in. |
| Wheelbase | - | 1,445 mm / 56.9 in. |
| Height | - | 1,150 mm / 45.3 in. |
| Length | - | 2,100 mm / 82.7 in. |
| Width | - | 845 mm / 33.3 in. |
| Weights & Capacities |
| Dry Weight | 176 kg / 388 lbs | 176 kg / 388.0 lbs |
| Fuel Capacity | 16 L / 4.2 US gal | 13.50 litres / 3.57 gallons |
| Wet Weight | - | 192.0 kg / 423.3 lbs |
| Performance |
| Max Power | 31,4 kW / 43 hp @ 6000 rpm | - |
| Max Torque | - | 68.00 Nm (6.9 kgf-m or 50.2 ft.lbs) @ 5750 Revolutions |
| Power-to-Weight Ratio | - | 0.4261 HP/kg |
| Engine |
| Fuel Control | - | Desmodromic valve control |
| Engine Type | - | V2, four-stroke |
| Displacement (ci) | - | 49.00 cubic inches |
| Displacement (cc) | - | 803.00 cc |
| Bore x Stroke (mm) | - | 88.0 x 66.0 mm |
| Bore x Stroke (in,) | - | 3.5 x 2.6 inches |
| Displacement | 646 cc / 39.4 cu in | - |
| Engine Detail | Four stroke, pushrod parallel twin, OHV, 2 valves per cylinder, | L-twin |
| Fuel System | - | Injection. EFI, 50 mm throttle body |
| Bore x Stroke | 72 x 79.3 mm | - |
| Compression Ratio | 7.5 : 1 | - |
| Cooling System | Air cooled | - |
| Emissions | - | Euro 3 |
| Exhaust | - | Single stainless steel muffler |
| Fuel Induction | Carburetor | - |
| Ignition | 6 V (After 1964 12 V) Magnet (Lucas K2F) | - |
| Starter | Kick | Electric |
| Valve System | - | 2 |
| Drivetrain |
| Clutch | Multi Plate (dry, Burman) | APTC wet multiplate with mechanical control |
| Final Drive | Chain | Chain |
| Gearbox | - | 6-speed |
| Transmission / Drive | 4 Speed | - |
| Chassis |
| Frame Type | Single cradle | Tubular steel Trellis |
| Suspension - Front | Hydraulic telescopic fork | Upside down Kayaba 41 mm fork |
| Suspension - Rear | Dual chocks | Kayaba rear shock, pre-load adjustable |
| Rake | - | 24.0° |
| Seat | - | Ribbed seat |
| Trail | - | 112 mm / 4.4 in. |
| Wheel Travel - Front | - | 150 mm / 5.9 in. |
| Wheel Travel - Rear | - | 150 mm / 5.9 in. |
| Electrical Systems |
| Instrumentation | - | LCD instrument panel |
| Wheels & Brakes |
| Brakes - Rear Diameter (mm) | - | 245 mm |
| Brakes - Front Diameter (mm) | - | 330 mm |
| Brakes - Rear Diameter (in.) | - | 9.6 inches |
| Brakes - Front Diameter (in.) | - | 13.0 inches |
| Brakes - Front | Drum | Single disc. ABS. Four-piston calipers. |
| Brakes - Rear | Drum | Single disc. ABS. Floating disc. Single-piston caliper. |
| Rims | - | Spoked aluminium wheels |
| Tyres - Front | 3.25 -19 | 110/80-ZR18 |
| Tyres - Rear | 3.50 -19 | 180/55-ZR17 |
| Wheels | Steel, wire spokes | - |