The Triumph Silver Jubilee Bonneville’s reign was short-lived

by Roland Brown
26 May 2022 4 min read
The Triumph Silver Jubilee Bonneville’s reign was short-lived
Photos: Roland Brown

Triumph’s promotional film for the 1977 Silver Jubilee Bonneville was a classic that still resonates today. A middle-aged former biker, having abandoned motorcycles to mortgage, marriage and kids, catches sight of the Bonnie on TV – and something snaps.

He leaps up, digs out his old helmet, goggles and riding jacket, and rushes out to blow the contents of his building society account on a silver 750cc Triumph. Moments later he’s cruising down the road, huge grin on his face, totally rejuvenated by the best of British biking.

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This year’s Platinum Jubilee is another 45 years on, but the Silver Jubilee Bonneville still shines brightly. Cruising through tranquil Surrey countryside, with the parallel-twin motor delivering torquey low-rev performance and the soft, deep exhaust note providing a stirring soundtrack, the Triumph highlights the appeal of classic motorcycling.

Before I’m accused of viewing the Bonneville through rose-tinted goggles I’ll add that it had earlier annoyed me with several ailments, ranging from leaks to a notchy gearbox. Compared to Japanese rivals led by Suzuki’s fast and fine-handling GS750 four, which was released in the same year, the Bonneville was old when it was new. But if the limited-edition model that Triumph created to honour Queen Elizabeth’s quarter-century on the throne had its faults, it also had plenty going for it.

The Triumph Silver Jubilee Bonneville's reign was short-lived

Back in 1977, creating a special Bonneville to mark the Silver Jubilee offered a welcome sales opportunity to a firm in terminal decline. In those days Triumph’s factory at Meriden, in Coventry, was being run by the workers’ co-operative that had taken control after a sit-in that had begun four years earlier, following management plans to shut the loss-making factory and move production to BSA’s plant in Birmingham.

The Jubilee bike was essentially a cosmetic update of the standard T140 Bonneville, the 744cc, twin-carburettor roadster that dated back to the original 650cc T120 Bonneville of 1959. Its main feature was the special silver paint scheme with red, white and blue highlights, plus extra chrome on parts including forks, engine covers and rear light.

The seat was blue with red pinstriping; and the wheels, which were originally fitted with Dunlop Red Arrow tyres, featured red, white and blue rims. Like the standard Bonnie the Jubilee was built both in UK and American export spec, the latter with higher bars and smaller petrol tank. It came with a signed certificate of authenticity from Triumph, and with approval from Buckingham Palace.

This well-preserved UK-market model felt light and compact as I threw a leg over its seat; not surprising given its weight of just 187kg. After I’d turned on the ignition near the left headlamp bracket and applied the carb-mounted choke, a gentle kick (no electric boot to help here) was enough to fire-up the motor, which came to life with a muted but pleasant twin-cylinder exhaust note.

First impressions were mixed. The combination of slightly upturned bars, forward-set footpegs and thick dual-seat was comfortable in town, and allowed a slight crouch into the wind that made higher speeds painless on more open roads. The motor pulled well at low revs but felt woolly in the midrange and wouldn’t rev out – until I realised the choke was vibrating partly shut.

Tightening a screw with a coin (a period accessory these days) cured that problem and the Triumph then ran much better, still hesitating slightly at about 55mph in top before clearing to pull strongly until the inevitable parallel twin vibration began to intrude. Peak output was a claimed 52bhp at 6200rpm, giving a top speed of just over 110mph. At an indicated 75mph the Bonnie was reasonably smooth, but upping the revs increased the buzz through seat and footpegs.

Triumph Silver Jubilee Bonneville

The motor lost marks in a couple of other ways, too. After stopping to top up with petrol I was less than impressed, though hardly surprised, to notice several black oil spots under the engine. Shortly afterwards I was miffed to find petrol soaking the right leg of my jeans, thanks to a leaky filler cap.

Another irritation was the gearchange, which was horribly notchy. Many enthusiasts reckon Triumph’s left-foot change was never as good as earlier right-footers, but most T140s (including the two I’ve owned) shift much more smoothly than this one, which required a firm left boot.

There was very little wrong with the handling, which in ’77 was good enough to let the Triumph keep up with all but the hardest ridden opposition, at least on a twisty road. Stability was excellent and the steering, although heavy by modern standards, allowed the Bonnie to be flicked around with satisfying ease.

Triumph Silver Jubilee Bonneville classic bike review

This bike’s forks felt slightly harsh despite the rubber-mounted bars, but the simple Girling shocks gave an impressively plush ride. The narrow tyres gripped fine, and the single disc brake at each end worked pretty well although the front lacked feel. Thankfully I didn’t have the chance to discover whether the old problem of delay in wet weather was still an issue.

Such tribulations were frequent back in 1977, and didn’t prevent the Silver Jubilee Bonneville from being a success for ailing Triumph, despite costing £1149 to the standard T140’s £1012. The firm had planned a limited edition of 1000 bikes for the US market, plus 1000 for Britain and elsewhere, and had to build an extra 400 machines in November to satisfy demand.

But although the Jubilee’s sales helped make 1977 a promising year for the Meriden co-op, the workers’ optimism proved misplaced. Shortly afterwards, the weakening dollar was partly responsible for a sales slump in Triumph’s vital American market, while debts continued to rise. Production was drastically cut; more workers were made redundant. Although Meriden struggled on long enough to introduce electric-start and eight-valve versions of the Bonnie, the end finally came in 1983.

Since then, of course, John Bloor has made Triumph great once again, while Queen Elizabeth has continued majestically on to her 70th year on the throne, albeit with a few family-generated bumps in the road. A new-generation Platinum Jubilee Bonneville would surely be well deserved.

1977 Triumph T140 Bonneville Silver Jubilee

You’ll love: Regal charm and poise
You’ll curse: Vulgar vibes and leaks
Buy it because: Stylish Seventies souvenir

Condition and price range: Project: £6000; Nice ride: £8,000; Showing off: £10,000
Engine: Aircooled parallel twin
Capacity: 744cc
Power: 52bhp @ 6200rpm
Weight: 187kg without fluids
Top speed: 115mph

Read more

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  • John LIGHTFOOT says:

    I had a 1968 BSA ROYAL STAR TWIN

  • Jerry G Orr says:

    I want to find one.

  • Barry C. Brown says:

    And there is the demise of the British motorcycle industry, in a nutshell. An ancient engine, unsophisticated, stodgy styling, leaking, creaking… an utterly crap ‘bike. And that was when it was new! I despaired at the time, and bought a new Honda CB750 in 1972, BECAUSE of this old rubbish. This Jubilee ‘bike was 5 years later and nothing had changed. Says it all. I’m so angry at the old British ‘bike industry for collectively destroying their market. The writing was there for all to see over TEN YEARS before, yet nothing was done – Doug Hele had to develop the three cylinder Trident/Rocket Three in secret because his bosses would have stopped the programme! In 1965, in the market for a new 250cc ‘bike, I looked ay what was on offer and quickly by-passed the BSA C15, Triumph’s Tiger Cub, Ariel’s Arrow and various Villiers-engined ‘bikes, looking closely at Honda’s beautifully engineered CB72, before choosing the fantastic Yamaha YDS3.
    The British ‘bike industry as it was is unlamented by me – it needed to go and full marks to John Bloor… well-deserved success and my thanks for creating a NEW British ‘bike tradition, one we can actually be proud of.

  • Tim says:

    Nice article – I remember them when they first came out!

  • Jerry G Orr says:

    I would like to purchase this.

  • Mark Rae says:

    Mines for sale. Pretty bike, 5k miles.

  • gavin Harvey says:

    I have one for sale £5750

  • Troy Nicholson says:

    I have a 77 silver jubilee for sale.

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