The Bite Magazine - Autumn/Winter 2022 - Issue 32

bitewatches Raymond Weil F rom 1959 to 1983, the 650 cc parallel-twin Triumph Bon- neville T120 motorbike based on the Tiger T110 was initially made by Triumph Engineer- ing. It was named after the Bonneville Salt Plains in Utah, USA, where Texas racer Johnny Allen established a record of 193 mph in a Triumph-powered streamliner. It was also influenced by the four-stroke parallel-twin Thunderbird cre- ated by motorcycle designer Edward Turn- er and driven by Marlon Brando in The Wild One. Triumph Motorcycles carried on the T120 until 1988. Triumph Engineering began producing the 500 cc parallel-twin engine with a two-cyl- inder, air-cooled OHV (overhead valve) motor in 1937 and increased its engine displacement to 650 cc in 1950. Six years later, an alloy cylinder head replaced the cast iron head, featuring bigger valves, better flow and cooling and allowing high- er compressions to be run. The new ‘Del- ta’ alloy head was initially designed for a single carburettor, but before long, a two- carb version replaced it. The same engine capacity powered the Tiger T110 and Bonneville T120, but the latter was equipped with two 1-3/16" Amal Monobloc carburettors instead of one. It also had a high-performance camshaft that gave it extra power to overwhelm the old duplex chassis, preceding a new twin-cradle frame in 1960. Between 1959 and 1962, the Triumph Bonneville had a separate engine and transmission, with the crankcase and primary case bolted to- gether with brackets in the frame.