Monday, May 2, 2011

AJS V4!... $#*!

For me, this, The Triton and the Pre Unit Drag Bike stole the show...
Here some info - courtesy of good old Wikipedia...

The AJS V4 (1935 – 1939) started out as a prototype air cooled V4 road bike, but became a water cooled and supercharged racing bike.
In 1935, at the Olympia Show, the Bert Collier designed air cooled sohc AJS 50° V4 was first displayed. It was a fully equipped road going version, which did not make it into production. This first version used a common crankcase with four individual cast iron cylinders and separate alloy heads, with exposed hairpin valve springs, and a 180° crankshaft with forked conrods. There was a central carburettor for each pair of cylinders, and fore and aft exhausts. The single overhead camshafts were chain driven. It had chain primary drive in an oil bath primary chain-case, and a wet clutch. It was stated by AJS at the time that there would be the option of replacing the forward mounted chain driven dynamo with a supercharger. The AJS used a rigid frame with girder forks.[1]

Forward 4 years...
In 1939 the 405 lb (184 kg). dry sump V4 was the first bike to lap the Ulster Grand Prix course at over 100 mph (160 km/h). Then World War II intervened.[2]

In June 1946, the AJS V4 finally won, at Chimay in Belgium, ridden by the same Jock M West who had defeated the AJS on a BMW in the TT before the War, and was now AJS Sales Manager. Walter Rusk did not survive the War, and Jock's mount was the bike Rusk had ridden. A week later at Albi, France, Jock West was in the lead when a crankpin seized and locked. (When Sammy Miller acquired the engine from Jock West thirty years later to rebuild the AJS V4 for his museum, he found the crankpin still seized.)[1]

AJS was already developing another supercharged engine, the AJS Porcupine, but, three months after the Albi race, the FIM banned all forms of forced induction for motorcycle racing.

The engine used by Walter Rusk in the Ulster GP, with 7.9:1 compression and 16.5 lbf/in² (114 kPa) of boost, made 55 bhp (41 kW) at 7200 rpm on a dynamometer.

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