Manufacturer Triumph Engineering Co Ltd Also called 6T, TR65 Production 1949–2003 (not continuous) Predecessor Speed Twin Engine Four-stroke Parallel-twin Power 34 bhp (25 kW) at 6300 rpm Transmission Four speed Wheelbase 55 in (1397 mm) Dimensions W 27.5 in (698.5 mm) Seat height 31.5 in (800.1 mm) Weight 385 lb (175 kg) (dry), 397 lb (180 kg) (wet) Related Tiger T110
The Triumph Thunderbird was a British motorcycle introduced in 1949 and produced in its original form until 1966. The name was used thrice more for new and distinct Triumph models.
To capture the American market, the 6T Thunderbird used a variant of the earlier Speed Twin's parallel twin engine, bored out from 500 cc to 650 cc to give the added horsepower American customers demanded.. The concept of enlarging the Speed Twin, the Thunderbird name and its 'paper dart' logo were thought up by managing director Edward Turner on one of his regular trips to Triumph's operations in the USA. The 'paper dart' logo was embossed onto the chain case cover on Thunderbirds from 1955 to 1962 and can be seen upon closer examination on the supplied photograph. Previously, it appeared as a decal on the headlamp nacelle.
Triumph obtained further publicity with Marlon Brando's 1953 motion picture, The Wild One, in which he rode a 1950 6T Thunderbird. In the book Triumph Motorcycles In America (Brooke/Gaylin), there is reproduced a letter from Triumph's importers objecting to the producers as to the use of their machine in this film about rowdy motorcycle gangs.