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Velocette Venom

 

Velocette Venom

The Velocette Venom is a single cylinder four stroke British motorcycle of 499 cc made by Velocette at Hall Green in Birmingham.[1] A total of 5,721 models were produced between 1955 and 1970. In 1961 a production Velocette Venom set the 24-hour world record at a speed of 100.05 mph (161.01 km/h). It was the first motorcycle of any size to achieve an average speed of over 100 mph for 24 hours and to this date no other motorcycle of the same capacity has been able to equal this world record.[2] 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. However, although it had more power than the Venom, the Thruxton could not save Velocette.[1] Poor sales forced the company into voluntarily liquidation in 1971, with all the remaining stock and tools sold off to pay creditors.[3]

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 OHC engine.[4] The Venom had high quality chrome plating and was finished in black paintwork with gold pinstriping. The Venom was also ahead of its time in being one of the first to have glass fibre enclosure panels from 1960. These panels proved unpopular with the traditional buyers of Velocette singles,[5] as they extended from the front of the engine, level with the top of the crankcase, to the rear pillion footrests.[3]


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. 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.[4] At the rear was an unusual swinging arm design with two arms in place of the traditional two prong fork. Although this was effective, it was complicated to set up the 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.[3]

The Velocette Venom used Miller electrics up to 1962, with a belt driven dynamo. After 1962 this was upgraded 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.[3]

Eventually becoming the best selling 'flagship' of the Velocette motorcycle range, the Venom is now highly sought after as a definitive example of a British sports four-stroke single.[3]

Venom Scrambler

In December 1958,[6] the Velocette development team built off Venom off road motorcycles which were sent to the United States for evaluation in enduro events.[7] Built to the Viper Clubman standard and advertised with the slogan 'A winner in every respect', the Scrambler had a specially lightened frame, light alloy mudguards and high level enduro style exhaust pipes. A special off road Venom was given the name the 'Endurance'. Fitted with the Venom engine, this had a 21 inch front wheel, high handlebars and a small fuel tank, as well as full lighting so that it could be legally used on the roads.[3]

Venom Clubman

From 1960, Velocette produced the Venom (and the Viper) in a 'Clubman' racing version, fitted with TT Amal carburettors, a manually controlled BTH racing magneto (in place of the Lucas unit) and a close ratio gearbox, with the compression ratio raised to 9.3 to 1.[5] The Venom Clubman dispensed with the glass fibre enclosure and instead made a feature of highly polished crankcase and gearbox castings. Supplied with 'rearset' controls, lowered handlebars and a steering damper, the Clubman also had a range of optional accessories including a 'megaphone' exhaust silencer, a rev counter and light alloy wheel rims.[3] Although they could be hard to start (with a whole section in the owners handbook on starting technique) experienced Clubman riders found them easy to maintain and fast, as the Venom Clubman could achieve over 100 mph.[8] In 1966 the Venom was upgraded to the Mk II, which had the Thruxton front forks fitted with rubber gaiters, a twin leading shoe front brake and narrowed mudguards which combined with s new exhaust design gave it a more modern sports motorcycle look.[3]

Velocette Venom Thruxton

Main article: Velocette Thruxton

In 1965, the well proven Venom was improved by Velocette designer Bertie Goodman with a special race kit complete with radically revised cylinder head, an Amal Grand Prix carburetor and reworked cam followers. The following year this went into production as the Velocette Thruxton. Also known as the Venom Thruxton, this aimed to fill the gap left by the demise of the BSA Gold Star and was named after the Thruxton Circuit race track on a former wartime airfield in Hampshire. The Velocette Thruxton was a true racer, with a full race specification cylinder head that was gas flowed by hand to accommodate extra-large valves and a downdraught inlet port. The Amal carburetor was so large it required a distinctive cut away in the bottom of the fuel tank and race cams boosted performance to up to 120 mph (190 km/h).[4] As well as the traditional black with gold lining finish, the Velocette Thruxton was also produced with an unusual blue frame, forks and seat and silver petrol tank with gold lining. In 1968 the Lucas magneto was phased out and Velocette replaced it with coil ignition.[9] A total of 1108 Thruxtons were built but although it had more power than the Venom the Thruxton couldn't save Velocette and the company was wound up in 1968, with remaining stock sold until mid 1970. The Thruxton has gone on to become one of the most sought after Velocette motorcycles today, however, and many private owners convert standard Venom models to the more valuable Thruxton specification.[1]

24-hour world record

On 18 March 1961 a production Velocette Venom Clubman set the 24-hour world record at an average speed of 100.05 mph (161.01 km/h).[10][11] It was the first motorcycle of any size to top the 100 mph in 24 hours, and to this date no other machine of the same capacity has been able to equal or improve on this record.[2] The record attempt took place at the Montlhery speed bowl, a 2.7 km (1.7 miles) concrete track just outside Paris with a very uneven road surface and poor track lighting.[12] A team of six French riders were accompanied by Motor Cycling journalist Bruce Main-Smith, who achieved the best lap time of 107 mph despite the poor lighting conditions. After securing the 12 hour record at more than 104 mph (167 km/h), the team went on to complete the 24 hour endurance record attempt. Stopping only to change riders and refuel (from a bucket using a funnel) the Venom secured the world record. The publicity was very important for Velocette, as the success revived sales of the Venom which went on to become one of Velocette's best selling motorcycles.[8] The Venom which set the 24 hour world record is now on display at the British National Motorcycle Museum.[13]

Racing success

The 'Thruxton' version of the Velocette Venom was ridden by Dave Dixon and Joe Dunphy won the Thruxton 500 endurance race. (In 1965 the race was actually held at another disused airfield, the Castle Combe Circuit). In 1967 two Velocette Venom Thruxton motorcycles, ridden by Neil Kelly and Keith Heckles gained first and second places in the Production TT that was first staged at the Isle of Man that year, with Kelly also recording the fastest lap at 91 mph.[1] Prepared by London Velocette dealer Reg Orpin, the winning motorcycle was far from standard, for as well as being in 'Thruxton' trim, the valve gear included titanium tips to the pushrods and valve caps. A Norton Manx piston had been specially engineered at Velocette's Hall Green Workshops and it had cam followers on needle rollers as well as light alloy timing wheels. It was nearly all for nothing, however, as Kelly failed to start and the rest of the field left him struggling to kick start the Venom. Orpin managed to start it just in time and despite the poor start Neil Kelly caught up with the other riders within three miles and went on to win the 500 cc class, recording 121 mph as he passed the Highlander speed trap.[8]

See also

References

External links

  • 1969 Velocette Venom reviewed
  • Velocette Venom video
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