Classic Motorcycle Build

Triumph Trident (1968-1975)

Twin-cylinder British motorcycles ruled until the late sixties, until demands from the U.S. market called for larger and more powerful bikes. As early as 1962, Triumph and their parent company BSA were working collectively on a multi-cylinder engine design. The goal was a 750cc machine without the vibration associated with the parallel-twin design, and without the bulk of a four-cylinder layout.

Triumph Trident History

By 1965, engineer Bert Hopwood and designer Doug Hele had a running three-cylinder prototype. Based on the existing parallel-twin, the OHV motor was slightly under-square, using a 67mm bore by 70mm stroke. The crankshaft rotated in the same direction as the wheels, with a primary drive chain connecting the crank to the multi-plate clutch. Final drive was also chain. Each cylinder had its own Amal carb, and the ignition system used three sets of points, each with its own coil.

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The Trident/BSA Rocket-3 was the first cooperative venture by BSA and Triumph since the companies merged in 1951. The BSA Company chose to produce their own version of the triple-cylinder bike, which used a different, forty-pound heavier frame. This delayed production of both models for over a year.

Triumph Trident T150

Triumph Trident History

The Triumph Trident and BSA Rocket 3 were finally available to the American market in 1969, the former keeping its single-downtube frame and holding the motor vertically, while the latter used a double-loop downtube, pitching the cylinders forward. Producing 58 horsepower at 7250 rpm, the Trident could cover the standing quarter-mile in under 13 seconds, and reached a top speed of 115 mph.

This new 500 pound "large-displacement touring machine" was regarded by many at the time to be the best road bike of all time - but not for long. Honda released its CB750-4 in the summer of 1969, a motorcycle that had everything the American market was looking for: electric start, front disc brakes, five-speed gearbox, and left-side shift - all standard. This was the beginning of the end for the British motorcycle industry.

Triumph Trident T150V

In 1972, the four-speed Trident was upgraded to a five-speed, and now called the T150V. The front drum was replaced by a ten-inch disc brake, and the steering damper found on earlier models was deleted. Electric-start Tridents started appearing in late 1974 as 1975 models.

Triumph Trident restoration by Mark Trotta

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Trident T160

The T160 was the final incarnation of the Triumph Trident. A new steel frame, whose design owed much to Triumph's successful factory production racers, had the Trident sharing the Rocket's forward-sloping cylinders. New front forks were slightly steeper and shorter, and pivoted on taper-roller steering head bearings. The new swing-arm was longer. Also new were the seat, side-panels, exhaust system, and 5.8 gallon tank.

Whereas the T150 was kickstart only, the T160 was fitted with both kickstart and electric start. Compression ratio was increased from 8.25:1 to 9.5:1, raising power output to 58 horsepower. Capable of 120-mph, the Trident T160 is regarded by many to be the definitive British superbike.

1975 Triumph Trident T160

The Triumph Company had suffered terrible financial losses by 1971. With their government intervening, they merged with ailing Norton, who had recently merged with Villiers. The new company, calling themselves Norton-Villiers-Triumph (NVT), carried on for several more years, but was never able to rebound. By 1976 both Triumph and BSA were gone. In all, over 27,000 Rocket3/Tridents were produced.

Tridents On The Racetrack

Tridents were one of the most successful race bikes of their time, dominating the 750cc races in Europe and in the U.S. In the early seventies, Trident Triples scored dozens of wins at tracks such as Mallory Park, Brands Hatch, Le Mans, Talladega and Thruxton.

At their first Daytona outing in 1970, Tridents took the top three qualifying speeds, with a high speed of 165.44 mph, and finished in second and third place. In the 1971 Daytona race, Tridents finished first, second and third. First place went to Dick Mann, who had won the year before on a Honda. Subsequent racing seasons yielded many more victories at the hands of riders such as John Cooper, Ray Pickrell and Percy Tait.

Perhaps the most famous racing Triumph was the production racer nicknamed 'Slippery Sam.' This race-prepared Trident took fourth place in its first year at the Isle of Man Production TT, and won first place in the next five consecutive Isle of Man races (1971 to 1975).

Slippery Sam Triumph Trident

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