The Triumph Bonneville was a survivor. Clearly based on Edward Turner's pre-war concept, it upheld traditional values while adopting the modern conveniences demanded by a new generation. Despite a number of obvious shortcomings, it won admirers throughout the superbike era.

The last of the long line of Triumph twins had an inauspicious beginning, when its launch was delayed by design problems. It began in 1971, in 6S0cc form with a new frame heavily based on the BSA A65, sharing its oil-in-frame design, with similar shortcomings as a result of an excessively high seat. By now, 'mod-cons' such as indicators were the norm, but with its drum brakes and kick-start, the TI20 Bonneville was years behind the Honda 750 Four launched three years earlier. Vibration and oil consumption were also a problem, but even the Japanese competition could not match the handling.

The first 750cc versions appeared the following year as the TI40V. Essentially, this was a bored-out 650 and, apart from minor variations, it shared the smaller bike's cycle parts, which now included a new front disc brake. The first few models were 724cc, but this soon settled at 744cc with a slightly larger bore. More softly tuned than the 650, the engine was also strengthened, with more positive location for the head and an extra holding-down stud; the transmission was beefed up, and there were other detail changes.

The parallel twin's vibration was worse on the new model, and it was slow to gain acceptance, especially while the 650cc ran alongside it. Worse still, the Meridien factory's problems reached a head late in 1973, ultimately resulting in the workers' occupation. No new machines appeared until mid 1974, and those that did emerge showed evidence of hasty finishing. The following year matters improved as the workers' cooperative got underway and settled down to doing what they knew best. Existing machines were sold off to make way for a new model, with an engine that had been modified to suit the American market's insistence on a left-foot gearchange - a regulation that was introduced in 1974. problem with antiquated machinery and limited funds, but by 1977 the factory was able to offer a limited edition Jubilee model, to mark the Queen's Silver Jubilee. With a number of minor refinements introduced in 1978, the TI40, as the model was now styled, had become a reasonably sound, if anachronistic, option.

The year 1979 brought the launch of the TI40E and the TI40D, a custom special. Around 20,000 machines based on the new design were built before Triumph finally went to the wall. These

version, a trail variant and finally the eight-valve TSS and custom TSX.

The Meridien cooperative went into liquidation in 1982 and the assets were bought by John Bloor who assigned limited rights to build the Bonneville to Les Harris's Devon based company. Harris built a limited number of Bonnies between 1985 and 1988, but although this spelt the end for the old twin, by then Bloor's own plans to write a new chapter in the Triumph story were wel[_ advanced.