Triumph Bonneville 1968-70: Collectable

Date 04.9.2015

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  • Motorcycle Trader


1968-70 Triumph Bonneville 

A great wine, such as a Grange Hermitage or Chateau Lafitte, will always have a vintage year where the weather conditions were just perfect and the grapes were at their peak. The same can be said about certain motorcycles, and the 650cc T120 Triumph Bonneville is a particular case in point.

Rather than the variability of climactic conditions, motorcycles can suffer from poor managerial decisions or the demands of the marketplace. This is especially appropriate to the T120 Bonneville that was Triumph’s production mainstay from 1959 until 1974, along with the single-carb Trophy.

Ask any Triumph enthusiast for an opinion on the vintage years for the Bonneville and inevitably the years from 1968 until 1970 will be mentioned. Before 1968 the Bonnie was afflicted with marginal electrics, handling and brakes and, after 1970, there was the debacle of the Umberslade Hall-designed oil-in-the-frame version.


If one bike typifies the ’60s it is undoubtedly the Bonnie. Because they were so ubiquitous to so many older enthusiasts today, it’s the one bike that epitomises youth. By 1972 it is understood that some 250,000 Bonnevilles had been built – at least three times as many as any comparable Norton or BSA twin. The Bonneville also offered an unparalleled balance between looks and performance at a competitive price – and a timeless appeal – and the ones to have were from that pinnacle period, 1968 to 1970.


Yet it was considerably earlier that the Bonnie was conceived. In recognition of the speed records at Bonneville, Triumph boss Edward Turner decided to make the most of this association and, in 1959, Triumph released the T120 Bonneville.

This was intended intended to be the performance flagship, but initially still very much a 650cc T110 Thunderbird hybrid. Performance was boosted over the 110 through the use of a splayed-port alloy cylinder head, higher compression, and twin Amal monobloc carbs without air filters. With 46 horsepower at 6500rpm, the Bonneville was claimed to be the fastest production bike available, a claim substantiated in 1961 when the British motorcycle press tested a T120R at 188km/h.

The first unit-construction Bonneville appeared in 1963, and initially wasn’t as highly rated as the pre-unit predecessors. While there were gains in the frame, which reverted to the classical Triumph single downtube, the unit-construction engine lost out in smoothness and electrical reliability.


Where the new T120 really scored over the pre-unit 650’s, however, was in compactness and weight. At 165kg it was nearly 14kg lighter, and this contributed to brisker performance. Every year saw a range of detail improvements, in particular from 1966, but with 1968 came one of the three top years. A new 8.0-inch twin leading-shoe front brake, two-way damping in the front fork in light of racing experience, and a stronger race-bred swingarm contributed to superior handling.

This was a particularly trying time at Meriden financially, and politically, and most resources were being poured into developing the new triples.


By now the 650cc engine had reached the zenith of its development as a competition unit and the Umberslade oil-in-the-frame models were waiting in the wings. But the late 1960s were real boom years for sales in the US, with more than 30,000 Triumphs sold in 1969.

While Meriden was flat out meeting demand, with production up to about 900 units a week, quality varied considerably, and the factory never really mastered the high-volume/high-quality equation that ultimately contributed to its downfall.


After 1970, just as the T120 seemed to represent the distillation of everything that was right about motorcycle styling, the expensive new R&D facility at Umberslade Hall gave birth to the inferior oil-in-the-frame replacement.

When it appeared, enthusiasts were mortified. Gone were the classic mufflers, gaitered fork, bullet-shaped headlights, and rounded side covers that epitomised Triumph. What’s more, the new double-cradle frame was so tall that the seat height was a towering 876mm, and a series of initial production problems got them off to a very shaky start. Eventually, the oil-in the-frame twins became solid and rideable motorcycles but, looking back now, Triumph enthusiasts lament that the 1970 models were “the last of the good ones”.

Given some of the reliability problems of the late ’60s, the use of the word ‘good’ is dubious, but what is undeniable is that they were the last of the classic Triumphs, and among the best-looking motorcycles ever made.

Watch out for a new Bonneville to be released next year featuring liquid cooling and, at last, a new frame.



New $995
Fair $10,000
Immaculate $15,000-plus


In the 1950s just about every motorcycle manufacturer was after “The World’s Fastest Motorcycle” title, in particular NSU, Triumph and Vincent. The year 1955 saw New Zealanders Bob Burns and Russell Wright take their Vincent Black Lightning to a record-breaking 298km/h on a road outside Christchurch, followed shortly after by Johnny Allen on his 650cc Triumph streamliner at the Bonneville salt flats in Utah, US. Allen hit 311km/h, but the record wasn’t recognised by the FIM on a technicality.

Triumph was unperturbed. In its eyes, and those of the US press, it still had the world’s fastest motorcycle. The following year, in 1956, Allen again returned to
Bonneville, this time achieving 345km/h, but once more his record wasn’t accepted by the FIM. Again it didn’t matter, and from 1955 until 1970, except for a brief period when NSU held the record, Triumph could legitimately claim the title of “The World’s Fastest Motorcycle.”

From 1964 the Bonneville formed the basis of Triumph’s production racing program, and it was developments from this that ensured the excellence of the T120 from 1968. In 1967 ex-works MV Agusta rider John Hartle won the first Isle of Man production TT, setting the stage for a series of memorable results, not only at the Island, but also in the Barcelona 24-Hour race.

Malcolm Uphill’s standing-start lap of 100.9mph (162.4km/h) was the first-ever 100-mph lap by a production machine at the Isle of Man and saw Dunlop rename its K81 tyre the TT100 to commemorate its involvement in the victory.

Following what became known as “the caught case” where a rider in the US had become emasculated by the traditional tank-top luggage rack in an accident and had sued the company, the tank parcel rack was deleted on US models from 1967, and from 1969 on the rest of the range. After appearing in court in a nappy, the rider had been awarded considerable damages.

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