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| {{Motorcycle
| | #Redirect [[AJS 500 Supercharged V4]] |
| |name = Racing Bikes AJS500 Supercharged V4
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| |photo=AJS-500-Supercharged-V4.jpg
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| |aka =
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| |manufacturer =
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| |parent_company =
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| |production =
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| |predecessor =
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| |class = Racing
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| |engine =
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| |compression =
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| |power =
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| |ignition =
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| |battery =
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| |transmission =
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| |frame =
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| |suspension =
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| |brakes =
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| |front_tire =
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| |wheelbase =
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| |length =
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| |related =
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| }}
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| == Photos ==
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| [[File:AJS-500-Supercharged-V4.jpg|600px|Racing Bikes AJS500 Supercharged V4]]
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| [[File:upercharged-AJS-500-V4-(1939.jpg|600px|Racing Bikes AJS500 Supercharged V4]]
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| [[File:AJS-Four-1939.jpg|600px|Racing Bikes AJS500 Supercharged V4]] | |
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| == Overview ==
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| AJS 500 Supercharged V4
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| The thirties saw the age old dream of
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| multi-cylinder-engined motorcycles moving within the engineers grasp. Most
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| makers hurled themselves headlong into building the most complex machines ever
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| seen, and the day of the single-cylinder seemed definitely gone.
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| Supercharged Version
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| AJS exhibited a prototype touring bike with an air cooled V4 power unit at the
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| 1935 London Show, but it was never built in this form, though a racing version
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| appeared in 1936. it was replaced in 1938by a new supercharged version with the
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| blower mounted at the front of the engine. The bike was extremely fast - but it
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| overheated horribly. AJS designer Matt Wright went back to work and completely
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| revised his project in 1939, redesigning the cycle parts and adopting liquid
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| cooling.
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| Record Lap - and Retirement
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| At last the revolutionary double overhead cam V4 was competitive - but the march
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| of time prevented it from showing its full potential. The two V4s entered in the
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| Isle of Man Tourist Trophy at the beginning of June finished eleventh and
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| thirteenth after several stops for oil and water. The V4 was entered in the
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| Ulster Grand Prix. It was the heaviest bike in the race, but set a staggeringly
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| fast lap record - the first 100 mph lap of the Clady circuit - before its front
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| fork broke! The AJS V4 only reappeared a few more times in 1946 before it was
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| finally put out to pasture in a museum.
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| Specifications
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| Engine Water cooled 500 cc (50x63mm) four stroke V4
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| Power Output 55hp@7200
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| Valves Chain driven twin overhead camshafts
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| Fuel System Zoller supercharger
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| Transmission 4-speed gearbox; chain final drive
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| Suspension Girder fork (front) sliding pillar (rear)
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| Brakes Drum (front & rear)
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| Wheels wire
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| Weight 405 lb
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| AJS 500 Supercharged V4 1939 | |
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| 1939 A.J.S. FOUR. Pre-war there was no ban on
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| superchargers in road-racing and these instruments, all too rare today, were
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| used with some success by several British and many Continental factories. A.J.S.,
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| then actively supporting road-racing with factory riders and machines, had for
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| some years experimented with an air-cooled Vee-four when in 1939 they revealed
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| to the public their latest hopes of achieving an Island victory in the Senior
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| T.T.a Matt Wright-designed supercharged Vee-four with chain-driven single o.h.c,
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| twin magnetos, swinging-fork rear springing and water cooling.
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| It made its debut at Brooklands in May of that
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| year when Bob Foster took it on a few laps' "tour"its very first ride on a
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| track. A few weeks later it appeared at the "North West 200" meeting, and in the
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| meantime had been equipped with a waterpump outboard of the engine sprockets. At
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| the fall of the flag Foster was struggling with a flooding carburetter float
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| chamber.
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| Eventually he started a couple of minutes behind
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| the field but in eight laps he had screamed through the fieldonly to retire
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| with a blown gasket on lap 13his riding number was 13 too.
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| In the T.T., Walter Rusk and Foster both had to stop several times for fuel and
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| water and could only finish eleventh and thirteenth. Rusk, however, did notch
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| one really good point for the model when, in August !939> ne recorded the first
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| 100 m.p.h. lap of the Ulster G.P., held then on the Clady Circuitbut bad luck
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| dogged him and he was put out with a broken fork link. In this race he had
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| outpaced the blown Gilera four, and it is fair to assume that, but for the war,
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| this model would have been a real force to be reckoned with.
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| As it was, the machines made a few fleeting
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| appearances after the war but the "blower ban" saw them taken off the active
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| list. Today, all that remains is an engine unit, on show in the Beaulieu Museum.
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| BRIEF SPECIFICATION
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| Engine: Vee-four 500 c.c. o.h.c; watercooled; chain-driven supercharger in front
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| of engine; chain drive to camshafts.
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| Ignition: two twin-cylinder magnetos.
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| Transmission: chain via four-speed gearbox.
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| Frame: duplex cradle with swinging-fork rear suspension controlled by
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| "plunger-type" spring boxes.
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| Forks: girder pattern with rebound springs.
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| Supercharged AJS 500 V4 (1939
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| By 1930s Brit-bike standards, the AJS 500 V4 was pretty fancy. The bike was
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| fitted with a liquid-cooled, SOHC, 8-valve, 495cc V4, with a chain-driven Zoller
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| supercharger. With 55 horsepower at 7,200rpm (with the compressor running at
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| 16.5psi boost pressure) and a dry weight figure of 183 kilos, the supercharged
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| AJS 500 could hit a top speed of up to 216km/h, which must have been pretty
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| scary if you take into account the feeble drum brakes and the not-so-evolved
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| tire technology of that era.
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| British journalist Alan Cathcart had the opportunity to ride the only
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| surviving AJS 500 V4 during the Goodwood Festival of Speed, in England, a few
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| years ago. Here are a few excerpts from what he has to say about the machine:
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| Starting it is an acquired skill. You have to prime the supercharger to get it
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| to fire, so starting from cold requires a long-distance push with the throttle
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| held wide open. Eventually the engine starts burbling into life, before suddenly
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| catching and emitting a high-pitched rumble from the four megaphones bracketing
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| the rear fender. You then have to blip the throttle furiously to keep the plugs
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| clean, all the while aware of the muted whine of the Zoller compressor as a
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| background accompaniment to the engines organ concerto.
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| The AJS supercharged engine pulls lustily from under 2,000 revs and feels
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| surprisingly modern and sophisticated. In spite of the lack of a counterbalance,
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| theres no undue vibration and no vintage-style rattles and whirrs or extraneous
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| mechanical noise.
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| In tighter turns, the AJS swings more readily through the bends than bulkier
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| inline-fours like the 1950s Gilera and MV Agusta 500s Ive ridden. Its not as
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| agile as a single but no heavier-handling than a twin. But thats in slower
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| turns. Elsewhere, the AJS V4 is a real handful, especially in a straight line.
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| Indeed, riding the AJS 500 V4 made me realize you must re-learn your riding
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| technique to ride it. Basically, theres no such thing as part-throttle the
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| throttle must either be wide open or switched right off. Try it and it splutters
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| until the throttle is wide open again. Brake, point, squirt thats the secret
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| to supercharged success.
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| SOURCE:
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| == External Links ==
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| http://www.fasterandfaster.net/
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| [[Category:Racing motorcycles]]
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