Triumph Bonneville 'Thruxton'

 

The Thruxton version of Triumph's Bonneville took its name from the endurance race for production machines held at the eponymous Hampshire circuit. Newly arrived from Norton, Doug Hele was in charge of Triumph's Experimental Department, which was charged with developing the Bonnie into a race winner. The first batch of eight specially prepared Thruxton Bonnevilles was completed in 1964 and the model was first listed in Triumph's 1965 catalogue. For the 1965 season a further batch of 52 machines was assembled in May of that year. It is estimated that some 73 Thruxton Bonnevilles were produced between 1964 and the end of 1967.

In 1962, Tony Godfrey and John Holder rode T120 Bonnevilles to victory in the Thruxton 500 mile production endurance race. Despite Triumphs reluctance to take part in the racing scene, the fact that the ACU demanded homologation of production racing machines and the dealer race teams begging for works replica T120s led them to allow their Experimental shop to produce the race version of the T120R.

The machines received only the best components, precision-machined castings, paired crankcase halves and crankshafts, hand-finished ports, Thunderbird camshafts, and close-ration gearboxes. Initially there were 4 gears but this was eventually increased to 5 speed Quaife units.

About 55 (52?) Thruxtons were produced, starting with the first three in 1964, the majority in 1965, then the last few in 1966 and 1967. They were continually tuned and tweaked up until 1969.