Triumph T120 Bonneville 650
Triumph announced the ultimate expression of Edward Turner's 650cc pre unit twin in September 1958 ready for the 1959 season. Named the Bonneville in recognition of Triumph's record breaking success at the salt flats of the same name, the new machine replaced the Tiger 110 at the head of the sporting Triumph range. The significant difference between it and the Tiger 110 concerned the cylinder head which was fed by two carburettors on splayed inlets together with a higher compression ratio, resulting in a claimed 46bhp. The 1960 season machines adopted a new duplex frame and lighter styling, losing the headlamp nacelle and partially valanced mudguards which had graced the 1959 models, with further detail revisions to the frame occurring for the 1961 model season.
Triumph's Speed Twin had been one of the bikes that helped to set the pace before the war. After the conflict, the SOOcc Speed Twin spawned many descendants, from 350 to 7S0cc capacity. Above all others, the 650cc Bonneville became the bike that set the standard throughout the late 1950s and 1960s - the era of the Rockers and Cafe Racers.
The first 650cc Triumph appeared in 1949, when the softly tuned 6T Thunderbird showed its pace at the Monthlery speed bowl before going on sale the next year. The model was an excellent tourer. The first Triumph machine to bear the Bonneville name appeared in 1959. Based heavily on the Tiger I 10, the T120 was fitted with the twin carburettors, together with the hot E3134 inlet cam. With a power rated at 46 bhp, the model was already good for a comfortable I I5mph - but the engine had the potential to be tuned a lot hotter. From 1963 they gained a new frame, with extra bracing for the swinging arm and steering head and a new compact power unit. The steering angle was changed and improved forks were adopted.
All these improvements helped the Bonneville to match its rivals' all-round performance. In the styling stakes, however, it had no equal. Where the contemporary BSA was worthy but perhaps a little stolid, and Norton's offering lacked the absolute glamour of its racing forebears, the 650 Bonneville oozed get-up-and-go.
Thruxton 500-miler, covering three more of the top seven places.
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