| Year | 1950 |
| Bore x Stroke | 71 x 82 mm |
| Capacity | 649 cc / 40.0 cu in |
| Clutch | Wet, multiplate |
| Compression Ratio | 8.5:1 (Export), 7.0:1 (UK) |
| Cooling System | Air cooled |
| Dry Weight | 168 kg / 370 lbs |
| Engine | Four stroke, vertical twin, OHV |
| Exhaust | Two-into-two |
| Final Drive | Chain, 101 links |
| Frame | Brazed lug |
| Front Brakes | SLS drum, 7 in |
| Front Suspension | Telescopic fork, hydraulic damping |
| Front Wheel | 3.25 x 19 |
| Fuel Capacity | 13.6 L / 3.6 US gal / 3.0 Imp gal (US), 18 L / 4.8 US gal / 4.0 Imp gal (UK and export) |
| Gear Ratios | 1st 11.90:1 / 2nd 8.25:1 / 3rd 5.81:1 / 4th 4.88:1 |
| Ground Clearance | 127 mm / 5.0 in |
| Ignition | Lucas magneto |
| Induction | 1 x Amal Monobloc, 25 mm (1953: SU type MC2) |
| Max Power | 25 kW / 34 hp @ 6500 rpm |
| Rear Brakes | SLS drum, 7 in |
| Rear Suspension | Rigid, spring loaded saddle |
| Rear Wheel | 3.50 x 19 |
| Seat Height | 775 mm / 31 in |
| Source | Classic Britishs |
| Starting | Kick |
| Transmission | 4-Speed constant mesh |
| Wheelbase | 1403 mm / 55.25 in |
