AJS Model 31650 CSR Hurricane
| Make Model | AJS Model 31 650 |
| Year | 1963 |
| Engine | Air cooled, four stroke, pushrod parallel twin, OHV. 2 valve per cylinder, |
| Capacity | 646 |
| Bore x Stroke | 72 x 79,3 mm72 x 72.8mm |
| Compression Ratio | 7,5 : 1 |
| Induction | Carburetor |
| Ignition / Starting | 6 Volt na 1964 12 Volt Magnet (Lucas K2F) / kick |
| Clutch | Multi Plate (dry, Burman) |
| Max Power | 31,4 KW 43 hp @ 6000 rpm |
| Transmission / Drive | 4 Speed / chain |
| Frame | Single cradle |
| Front Suspension | Hydraulic telescopic fork |
| Rear Suspension | Dual chocks |
| Front Brakes | Drum |
| Rear Brakes | Drum |
| Front Tyre | 3.25 -19 |
| Rear Tyre | 3.50 -19 |
| Weight | 176 kg |
| Fuel Capacity | 16 Litres |
The AJS Model 31 CSR designation officially stood for Competition / Sport / Road but it was dubbed the Coffee Shop Racer by its rivals.[4] With its distinctive 2 into 1 'siamese' exhaust system and upgraded camshafts the CSR was a high performance motorcycle but still prone to leaks and vibration.
The factory diverted Chief Engineer Jack Williams from AJS 7R development to address the problems and modify the bikes for racing - with the result that Ron Langston and Don Chapman won the prestigious Thruxton 500 long distance endurance race on the AJS Model 31. Encouraged by this victory in 1963 the AJS Model 31 gained the name Hurricane).[5] By 1966 the company were in financial trouble and production ended.