AJS Model 31: history, specs, pictures
The AJS Model 31 650 Swift was a air-cooled, four-stroke, parallel twin cylinder, OHV, 2 valves per cylinder Classic motorcycle produced by AJS in 1957. Claimed horsepower was 43.05 HP (32.1 KW) @ 6000 RPM.
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| AJS Model 31 650 | |
| Manufacturer | |
|---|---|
| Also called | 650 Swift |
| Production | 1957 |
| Class | Classic |
| Engine | air-cooled, four-stroke, parallel twin cylinder, OHV, 2 valves per cylinder |
| Bore / Stroke | 71.1mm x 71.1mm |
| Compression ratio | 7.5:1 |
| Horsepower | 43.05 HP (32.1 KW) @ 6000RPM |
| Ignition | magneto |
| Transmission | Gear box: 4-speed, manual Final Drive: chain |
| Suspension | Front: telescopic fork Rear: dual shocks |
| Brakes | Front: drum Rear: drum |
| Front Tire | 3.25 -19 |
| Rear Tire | 3.50 -19 |
| Weight | |
| Fuel Capacity | 4.23 Gallon (16.00 Liters) |
| Manuals | Service Manual |
Engine
A 71.1mm bore x 71.1mm stroke result in a displacement of just 646.0 cubic centimeters.
Drive
The bike has a 4-speed, manual transmission. Power was moderated via the wet multi-disc, manual.
Chassis
It came with a 3.25 -19 front tire and a 3.50 -19 rear tire. Stopping was achieved via drum in the front and a drum in the rear. The front suspension was a telescopic fork while the rear was equiped with a dual shocks.
1957 - 1966 AJS Model 31 650
The 1957 AJS Model 31 650 has, at its heart, an air-cooled, four-stroke, 646cc, parallel twin powerhouse paired to a four-speed manual transmission, and can reach a maximum power output of 43 horsepower at 6000 rpm.
It comes standard with features such as a blacked-out frame, a suspension package composed of a front telescopic fork and dual shocks as a rear suspension, a dual seat, a chromed, dual exhaust system, laced wheels, full fenders, and a dual tone paint scheme.