2012-09-27 13:44:41+0000
  • Make:
  • AJS
  • Model:
  • 500cc Supercharged V4
  • Year:
  • 1939

The AJS 500cc Supercharged V4 is a British competition motorcycle built in 1939. It has a water cooled, four stroke V4, 500 cc engine.

‟The Thirties saw the age-old dream of multicylinder- engined motorbikes moving within the engineers' grasp. Most makers hurled themselves headlong into building the most complex machines ever seen, and the day of the single- cylinder seemed definitely gone.

Supercharged Version

AJS exhibited a prototype touring bike with an air-cooled V4 power unit at the 1935 London Show, but it was never built in this form, though a racing version appeared in 1936. It was replaced in 1938 by a new supercharged version with the blower mounted at the front of the engine. The bike was extremely fast - but it overheated horribly. AJS designer Malt Wright went back to work and completely revised his project in 1939, redesigning the cycle parts and adopting liquid cooling.

Record Lap - and Retirement

At last the revolutionary double-overheadcam V4 was competitive - but the march of time prevented it from showing its full potential. The two V4s entered in the Isle of Man Tourist Trophy at the beginning of June finished eleventh and thirteenth after several stops for oil and water. Then the V4 was entered in the Ulster Grand Prix. It was the heaviest bike in the race, but set a staggeringly fast lap record - the first 100mph lap of the Clady circuit - before its front fork broke! The AJS V4 only reappeared a few times in 1946 before it was finally put out to pasture in a museum.


  • Engine: water-cooled 500cc (50x63mm) fourstroke V4
  • Power output: 55 hp @ 7200 rpm
  • Valves: chain-driven twin overhead camshafts
  • Fuel system: Zoller supercharger
  • Transmission: 4-speed gearbox: chain final drive
  • Suspension: (front) girder fork; (rear) sliding pillar
  • Brakes: (front) drum: (rear) drum
  • Wheels: wire
  • Weight: 405 lb


The era of multicyclinders, the V4 AJS was an attempt to rival the powerfu1 continental hikes that dominated European Grand Prix racing, but it was not competitive.”

*This Atlas extra-large trading card is part of the EatSleepRIDE motorcycle stuff collection.

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