8th September 2020

Motorcycling Landmarks - The BSA/Triumph Triples

Few machines in the classic world divide opinion as strongly as the air-cooled triples produced from 1969-1975 - the BSA Rocket 3 and Triumph Trident. Some regard them as an under-developed engineering ‘lash up’; others as a world-beating and charismatic swan song for the old British bike industry. Though not ultimately a commercial success, they passed into legend for their many race victories, often in the teeth of fierce competition from Japan’s finest.

A prototype of the triple engine was running in a Triumph twin chassis in 1965 but management indecision delayed its launch until late in 68, spurred on by rumours of Honda’s impending CB750 four. Denied the investment for an ‘all new’ design, the engineers made the best of what they had, carrying over the vertically split crankcase arrangement used by the twins. For a three cylinder engine, this meant using three crankcase castings with all the associated machining costs and assembly complexity.

While the engineering was compromised by under-funding, the styling of both the BSA and Triumph versions was also to prove controversial. The ultra-modern designs, by Ogle, were generally considered a step too far for conservative motorcycle buyers, exemplified by the space-age silencers, nicknamed ‘ray guns’. Money was also wasted tooling separate engine castings for the BSA and Triumph models, in order to distinguish between them, but adding no technical benefit. The BSA cylinders sloped forwards; the Triumph cylinders stood upright.

While the styling did not excite the market, the performance certainly did. A 750cc triple capable of over 120mph and with a fine handling frame, whether BSA or Triumph, offered something more than the Japanese bikes, which still struggled with roadholding. To emphasise the point, BSA/Triumph embarked on a racing programme for the triples to generate as much favourable publicity as possible.

A mixture of production racing successes, using the standard frames, and open class racing victories, using the famous ‘Rob North’ frames, followed. In 1971 they dominated the Daytona 200-mile race, finishing 1-2-3, along with numerous victories in Formula 750. At the Isle of Man, the same Trident won the Production TT race every year for five years with different riders, an achievement without parallel.

The bike in question had a famous nickname, ‘Slippery Sam’, gained during the 1970 Bol d’Or 24-hr race. After switching from mineral oil to racing castor oil, its engine failed to scavenge properly and leaked oil all over the rear of the machine, causing the back tyre to slide unpredictably. Rider Percy Tait bravely pressed on and eventually finished 5th.

Another legendary result for a triple was beating Giacomo Agostini on a works MV 500 Grand Prix bike. The rider, John Cooper, was on a BSA racer at the 1971 Race of the Year at Mallory Park.

Such achievements helped to build the reputation of the triples but, throughout their production life, the retail bikes were dogged by reliability issues. However, in the decades since, a cottage industry has emerged within the classic world with the expertise to maintain and improve the machines so that many of them now run better than ever.