TRIUMPH BONNEVILLE. T120 .750 cc FOUR STROKE.

Manufacturer United Kingdom Triumph Engineering Co Ltd
Also called "Bonnie"
Production 1959–1972
Engine 649 cc (39.6 cu in) air-cooled, ohv parallel-twin
Power 46 bhp (34 kW) @ 6,700 rpm
Transmission 4-speed gearbox with chain final drive
Wheelbase 55 inches (1,400 mm)

The Triumph Bonneville T120 was a British motorcycle designed and built by Triumph Engineering Co Ltd between 1959 and 1972, when the engine size was increased to 750 cc (46 cu in).
Development

The Bonneville T120 was Edward Turner’s last production design at Triumph[2] (in retirement Turner designed the Triumph Bandit/BSA Fury which did not pass the prototype stage before BSA went under[3]). The new motorcycle was conceived and developed by Doug Hele[citation needed] and Brian Jones so quickly that it wasn’t even included in the 1959 Triumph catalogue.[4] With a 649 cc (39.6 cu in) parallel-twin (two-cylinder) engine the T120 was based on the Triumph Tiger T110 and was fitted with the Tiger’s optional twin 1 3/16 in Amal monobloc carburettors as standard, along with that model’s high-performance inlet camshaft.[1] Launched in 1959 by Triumph as "The Best Motorcycle in the World", the Bonneville T120 was aimed mainly at the lucrative US market where enthusiasts were demanding extra performance.[5]

Initially produced with a pre-unit construction engine which enabled the bike to achieve 115 mph (185 km/h) without further modification, the power tended to induce high speed wobbles from the single downtube frame,[1] so in 1963 a unit construction model was introduced which was stiffer and more compact, including additional bracing at the steering head and swinging arm.[1] The steering angle was altered and improved forks were fitted a couple of years later, which, together with the increased stiffness enabled overall performance to match that of the Bonneville’s rivals.[6]

Later T120 Bonnevilles used a new frame which contained the engine oil instead of using a separate tank; this became known as the oil in frame version. In 1968 the T120 gained a new and more reliable ignition system, but by 1972 competition from larger-capacity motorcycles led to the T120 being replaced by the 750 cc Bonneville T140.

Posted by ronsaunders47 on 2010-10-26 07:26:16

Tagged: , MOTORCYCLES , MOTORBIKES , CLASSICS , BRITISH , TRIUMPH , BONNEVILLE , T120

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