BSA ROCKET 3. 1968-1975

BSA ROCKET 3.  1968-1975

The BSA Rocket Three/Triumph Trident was the first true modern superbike and the last major motorcycle developed by the original (Triumph Engineering Co Ltd) Triumph company. It was badge-engineered to be sold under both the Triumph and BSA marques.

The Rocket3/Trident was the first-step development of Triumph Motorcycles’ plan to move on from the basic vertical twin. The engine was to give the 750 cc power required by the US market while avoiding the vibration associated with an increase in capacity of the existing parallel-twin design.

During its production run BSA fell into financial troubles,[1] and over the course of the official seven year model run approximately 27,480 Rocket3/Tridents were produced. By comparison, around a quarter of a million Honda Goldwing motorcycles were manufactured during its first seven years.
Although designed in the mid-1960s, the engine of the BSA Rocket3/Triumph Trident was based heavily on Edward Turner’s legendary Triumph two-cylinder 500 cc Speed Twin of 1937 and the next year’s sports model Tiger. Because of this, the three-cylinder Trident is sometimes known as the “Tiger 100 and a half”. However, when the bore and stroke are considered it is actually more like three C15 engines: the unit-construction T100 has a short stroke, unlike the triple’s 67 mm x 70 mm dimensions. The pre-unit 500 was 63 mm x 80 mm, as was "P1" – the first prototype Triple. When the rest of the engine layout is investigated, the T100 claim does look genuine. The separate camshafts from the Triumph engine are in evidence. This basic design was one of the most long-lived in motorcycling history, being used for over 40 years in Triumph’s entire range of vertical twins, including the legendary Triumph Bonneville.[2]

The three-cylinder design was started in 1962 by Bert Hopwood and Doug Hele. While design progressed, test engineers developed the handling of the chassis by loading lead weights onto a standard 650 Bonneville. With the first prototype (P1, which is now owned by the Trident and Rocket 3 Owners Club – TR3OC) running by 1965, it appeared that Triumph could have a machine in production by 1967. However, the decision to produce a BSA version with sloping cylinders and to employ Ogle Design to give the early Trident/Rocket3’s their modern ‘square’ look, not only robbed the prototype of its ‘lean’ looks and added 40 lb (18 kg) of weight, but also delayed production by 18 months. During 1966, a P2 prototype was produced with a more production-based Trident engine, with changed bore and stroke dimensions and improved cooling. Later, Doug Hele obtained 90 bhp (67 kW) from a Trident engine, suggesting that if development had sped up in 1964, a 140 mph (230 km/h) British Superbike would have been a reality in 1972.

Posted by ronsaunders47 on 2011-10-29 14:30:22


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