|
The Velocette Venom was a 499 cc single-cylinder four-stroke British motorcycle made by Velocette at Hall Green in Birmingham. A total of 5,721 machines were produced between 1955 and 1970. In 1961 a production Velocette Venom set the 24-hour world record at a speed of . It was the first motorcycle of any size to achieve an average speed of over 100 mph for 24 hours and, as at 2008, no motorcycle of the same capacity has been able to equal this record. In 1965, the Velocette Venom was further developed by Velocette designer Bertie Goodman to create the Velocette Thruxton, with a race specification cylinder head that was gas flowed by hand to accommodate extra-large valves and a downdraught inlet port. It was a very popular and successful clubman racer, but although it had more power than the Venom, the Thruxton could not save Velocette.〔 Poor sales forced the company into voluntarily liquidation in 1971, with all the remaining stock and tools sold off to pay creditors.〔 A further development was the ''Indian Velo 500'', an updated, limited-production run of 250 machines devised by American entrepreneur Floyd Clymer, using a Velocette engine with Italian cycle parts.〔 ==Development== Introduced in November 1955 and launched at the same time as the 349 cc Velocette Viper, the single-cylinder ''Venom'' was developed from the Velocette MSS and needed to compete against a new range of British twin-cylinder motorcycles. Conceived by Velocette’s Eugene Goodman and designed by Charles Udall, the Venom's 499 cc engine had a bi-metal cylinder with a cast-iron liner, high compression piston and a light alloy cylinder head. The design of the engine's high cam with short push-rods was simpler to produce than an overhead camshaft engine. The Venom had high quality chrome plating and was finished in black paintwork with gold pinstriping. The ''Sport'' models〔 of the Venom and the Viper were among the first production motorcycles to have glass fibre enclosure panels from 1960.〔 These ''quickly-detachable'' enclosures were produced for Velocette by Avon〔''The Classic MotorCycle'', July 1996, p.27 ''Shaping the Future'' by ''Roy Poynting. "Engine/gearbox fairing for the so-called Sports Velocettes was not a sales success story''". Accessed and added 2014-09-25〕 and extended from the front of the engine, level with the top of the crankcases, to the rear pillion footrests. Although a practical addition in preventing oil-stained clothing,〔''Motorcycle Mechanics'', April 1966. pp.60–61 ''Road test. "Another unique point about the Velo are the glass-fibre enclosure panels around both sides of the engine and gearbox. They cover all the lower parts of the engine and gearbox, and make the Velo one of the few bikes one can ride in decent street clothing without danger of oily smuts and splashes. The only tool needed to remove them is a bronze penny, and they come off within seconds"'' Accessed and added 2014-09-25〕 the panels were unpopular with the traditional buyers of Velocette singles.〔 An unusual feature of the Venom design is that the clutch was between the gearbox and gearbox sprocket rather than the conventional configuration in the primary chain case on the far left, with the gearbox sprocket between the clutch and the gearbox. This made the clutch less accessible but allowed for easy gearing changes and a range of sprockets with different numbers of teeth could be fitted by removing the sprocket cover.〔''Motorcycle Mechanics'', April 1966. pp.60–61 ''Road test'' Accessed and added 2014-09-24〕 The gearbox was also a novel Velocette design with a constant mesh close ratio unit that could be maintained relatively easily while still in place. Simply designed with single top and down tubes, the Venom's heavy brazed-lug frame (which had clear origins in bicycle manufacture) was well proven for its handling capability.〔〔''Motorcycle Mechanics'', April 1966. pp.60–61 ''Road test. "Built rather on the heavy side, the frame is a solid example of traditional British craftmanship, and coupled with the chunky Velo forks and the finely adjustable rear suspension, is responsible for the absolutely unshakeable steering. With the current rage for special building, one is tempted to wonder why the Velo frame and cycle parts are not more popular with the powerhouse Bonneville boys—..."'' Accessed and added 2014-09-25〕 At the rear was an unusual swinging arm design with two separate arms clamped to a cross-tube instead of the traditional welded-section rear fork. Although this was effective, it was difficult to set up the horizontal alignment. The rear shock absorbers were originally made by Woodhead Monroe, then replaced by Armstrong units and eventually Girling shocks. These could easily be adjusted to suit the rider's preference by moving them in special curved slots. The front telescopic forks, designed by Velocette and manufactured in-house, had hydraulic damping and an offset wheel spindle.〔 The Venom used Miller electrics up to 1962, with a belt-driven dynamo. After 1962 this was changed to a Lucas system. The speedometer, ammeter and light switch on the original Venoms were fitted into a steel headlamp nacelle; the optional rev counter had to go on a bracket. Later models with Thruxton forks had conventional headlamp brackets and separate instruments.〔 Eventually becoming the best selling 'flagship' of the Velocette motorcycle range, the Venom has become highly sought after as a definitive example of a British sports four-stroke single.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Velocette Venom」の詳細全文を読む スポンサード リンク
|