AJS Model 20 500: review, history, specs

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AJS Model 20
1955 AJS Model 20.jpg
Manufacturer AJS
Also called Model 20 500, Model 20 500
Production 1948 - 1959
Successor AJS Model 31
Class Classic
Engine 498cc air-cooled twin, four-stroke
Bore / Stroke 66.0mm x 72.8mm
Compression ratio 7.3:1
Top speed 85 mph (137 km/h)
Horse Power 19.58 HP (14.6 KW) @ 6800RPM
Ignition type magneto
Battery 7.0:1
Transmission Gear box: 4-speed

Final Drive: chain

Clutch: wet multiplate
Suspension Front: telescopic
Rear: twin shock
Brakes Front: expanding brake (drum brake)
Rear: expanding brake (drum brake)
Front Tire 3.25-19
Rear Tire 3.25-19
Dimensions L 86.22 inches (2190 mm)
W 27.95 inches (710 mm)
H 41.34 inches (1050 mm)
Weight 392.42 pounds (178.0 Kg) (dry), 178.0 kg (wet)
Fuel capacity 3.57 Gallon (13.50 Liters)
Manuals Service Manual
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The AJS Model 20 500 is a twin, four-stroke allround motorcycle produced between 1948 and 1959. It could reach a top speed of 85 mph (137 km/h). Claimed horsepower was 19.58 HP (14.6 KW) @ 6800 RPM. The Model 20 was finally discontinued when the 646 cc AJS Model 31 replaced it in the autumn of 1958.

Variants[edit]

The Model 20B was the model imported into the USA.


Engine[edit]

The engine was a air cooled twin, four-stroke. A 66.0mm bore x 72.8mm stroke result in a displacement of just 498.0 cubic centimeters. The engine features a 7.0:1 compression ratio.

Drive[edit]

The bike has a 4-speed transmission. The final drive was via chain. Power was moderated via the wet multi-plate.

Chassis[edit]

It came with a 3.25-19 front tire and a 3.25-19 rear tire. Stopping was achieved via expanding brake (drum brake) in the front and a expanding brake (drum brake) in the rear. The front suspension was a telescopic while the rear was equipped with a twin shock. The Model 20 500 is fitted with a 3.57 Gallon (13.50 Liters) fuel tank. The bike weighs just 392.42 pounds (178.0 Kg).


1948 - 1961 AJS Model 20 500[edit]

1948 - 1961 AJS Model 20 500

The 1948 AJS Model 20 500 has, at its heart, an air-cooled, four-stroke, 498cc, parallel twin cylinder powerplant mated to a four-speed manual transmission. It comes standard with features such as laced wheels, a suspension package composed of a front telescopic fork and dual rear shocks, a solo, sprung seat, wide handlebars, an analogue instrument cluster, a dual exhaust system, full-fenders, a blacked-out frame, and a large, 17-liter (4.5-gallon) fuel tank.