Saturday, September 21, 2013

Velocette Thruxton

Velocette Thruxton

From Wikipedia
Also calledVenom Thruxton
PredecessorVelocette Venom
Engine499 cc (30.5 cu in), OHV air cooled single
9:1 compression ratio
Amal 5GP2 13/8 carburettor
Top speed180 km/h (110 mph)
Power31 kW (41 bhp) @ 6,200 rpm
Brakesfront drum, 7.5 inch John Tickle 2LS, rear drum
Wheelbase139.1 centimetres (54.75 in)
Seat height30.5 inches
Weight180 kg (390 lb) (dry)
Fuel capacity4.5 gallons
Oil capacity4 pints
Fuel consumption60mpg at 65mph


The Velocette Thruxton is a sporting motorcycle made by Velocette. Revealed at the 1964 Earls Court Show and produced between 1965 and 1971, it was the final development of Velocette's antiquated pushrod single, the Venom. Sometimes referred to as the Venom Thruxton, many surviving examples are 'upgraded' replicas based on the Venom. The Thruxton ceased production only when the company folded in 1971.


An optional cylinder head for the Venom (possibly designed by either Lou Branch or Dick Brown) became available for racers in 1964; a Venom equipped with this revised cylinder head took first in its class at that year's Thruxton 500-mile (800 km) endurance race. Veloce introduced the Venom Thruxton production model in 1965 with an advertised 41 horsepower at the crankshaft. Period tests clocked it at 110 mph (180 km/h) without race tuning.
The well proven Venom was improved by Velocette designer (and owning-family member) Bertie Goodman with rearward placed footrests having brake pedal and remote gear-change linkage to suit, close-ratio four speed gearbox, alloy rims, twin-leading shoe front brake and 'clip-on' handle bars. The engine gained a race specification cylinder head to accommodate extra-large valves, a downdraught inlet port and an Amal 5GP2 13/8 bore carburettor with extended inlet tract which was so long it required a special cut out in the rear of the fuel tank. The upgraded engine delivered 41 brake horsepower (31 kW), 5bhp more than the Venom.
It was important for eligibility in endurance races such as the Thruxton 500 that competing motorcycles were genuine production machines, but although the Velocette Thruxton was sold in a road going version, it was really targeted at the racing fraternity.
No more than 1108 Thruxtons were manufactured before the company collapsed in 1971.

Racing success

Although named after the Thruxton 500 endurance race, for 1965 the race was actually held at another disused airfield, Castle Combe Circuit in that year. The Velocette Thruxton, ridden by Motor Cycle journalist David Dixon and Joe Dunphy, won the 500cc category.
In 1967 two Thruxtons, ridden by Neil Kelly and Keith Heckles gained first and second places in the 500cc Production TT, the first time a production-machine event had been staged at the Isle of Man with Kelly also recording the fastest lap at 91 mph.

Further Development

Geoff Dodkin and L.Stevens were two well-known specialist motorcycle retailers in the London area offering mechanical upgrades and cycle customising parts backed by their own race experiences. These included nimonic valves, larger lightweight aluminium oil and fuel tanks, seats, smaller megaphone silencers and an alloy top yoke.
The Avon Speedflow race fairing (made by Mitchenall Brothers) was introduced in 1964 in time for the June Isle of Man TT Races but the transparent, aerodynamic 'nose-cone' extending over the front race number plate area was soon 'outlawed' by the ACU, the UK motorcycle race-organisation governing body.
This led to the fairing being modified for a headlamp and offered for road use, complete with transparent nose-cone.
The Velocette Thruxton version was one of the first to be available, coming from the factory finished to match the standard Thruxton colour scheme in blue and silver or the optional black and silver.


These bikes handle and are very smooth when going at speed.  For such an antiquated design they do what they were intended to do, go fast through the twisties.