TRIUMPH THUNDERBIRD
Long-legged and easy to live with, the unit construction Thunderbird found favour with police forces worldwide. These days, says Rowena Hoseason, it’s also the most affordable of Triumph’s mid-1960s 650 twins…
Long-legged and easy to live with, the unit construction Thunderbird found favour with police forces worldwide. These days, says Rowena Hoseason, it’s also the most affordable of Triumph’s mid-1960s 650 twins…
Given its head in 1963, a Triumph Thunderbird swept Bob Currie to 102mph, oozing a deceptively laidback power delivery that was ‘so smooth as to be nigh-on liquid. No kick in the pants feeling, but an all the way push which sends the speedometer needle up in to the nines before you know it.’ One minute, Bob was noodling along at 30mph in top gear. Just 13 seconds later he’d accelerated cleanly to 80mph without swapping a single cog. That’s why the unit construction 6T was so popular with police forces across the UK and municipal fleets worldwide, to the extent that the scuffers’ bikes gained a special nickname – The Saint. It’s also one reason why the Thunderbird of the mid-60s is such an attractive classic rider’s machine today. There’s another very good reason for the 6T’s modern popularity: price. Unlike pre-unit Triumphs from the 1950s which will set you back a solid five-figure sum, their 1960s successors can be had for half the price… especially the not-so-sought after single-carb ‘touring’ 650. For many classic fans, the appeal of the Bonneville and Trophy twins is all but irresistible. But look beyond their immediate magnetism and you’ll see twin carbs and/or high compression, highly tuned engines with a steep price tag to match. Back in the day, the difference between 102mph and 112mph was vitally important. On a Sunday ride with your club section, you’re more likely to appreciate the Thunderbird’s tractability – and several thousand pounds in your pocket…
That bike which Bob rode was one of Triumph’s second phase of unit construction twins, the large capacity twins which were introduced in 1963. One of three 650s in the range, the single-carb Thunderbird took on the touring role. The new motor was certainly stiffer and sleeker than its predecessor, with a lighter flywheel, 3/8” duplex primary chain, stronger clutch and improved shock absorber. Out went the magneto, and in came points ignition. Multiple fixings now secured the cylinder head – hence this engine’s ‘nine stud’ nickname – and the new aluminium head boasted more fins for better cooling.
The engine sat in a new, single downtube frame and, arriving at the tail end of the era of bathtub bodywork, the unit Thunderbird retained a rear skirt, Triumph’s trademark nacelle and the voluminous mudguards
of an all-weather tourer. Many 6Ts were subsequently stripped back to bare essentials by boy racers, so an early unit Thunderbird with complete enclosures commands a price premium over the final, unfaired incarnations built in 1966.That may seem counter-intuitive, given that the last of the line benefitted from a range of improvements to performance, electrics, braking and such, but there’s another reason why the initial unit Thunderbirds have a good reputation.
In 1964, Harry Sturgeon took the reins at Triumph and he was determined to outshine Edward Turner and double the company’s output. Pushing production towards 4000 bikes per month inevitably led to short-cuts in component manufacture and machine construction. The workforce grew rapidly but the new men at Meriden didn’t necessarily have the experience to maintain machine quality. So although the final Thunderbird, like the 1966 model you see on these pages, theoretically boasts a better spec and sleeker lines, the 1963 machines definitely have a firm following.
Nor, as Bob Currie so ably demonstrated, did the big bodywork of the first Bird affect the 6T’s turn of speed. In fact – don’t tell any Trophy or Bonneville owners this – the softly-tuned Thunderbird is a lovely, lazy thing to live with. It might not reach 120mph but you don’t have to cope with a pair of carbs, either. Of the first generation 6T, Cycle World said ‘we simply cannot find fault with the ride and everything operates with great precision... the Thunderbird impressed us as being very much the gentleman’s motorcycle. It has been as
pleasant a motorcycle as any offered to us for test.’
So there’s a good argument for seeking out a 1963 T-Bird, bathtub and all. On the other hand, the 6T benefitted from the continual development of the 650 range throughout the 1960s. In 1964 it was the first Triumph to make the change from 6V to 12V. Detail tweaks followed in 1965. For its final year of production, the 6T was given Triumph’s latest frame – fine-tuned by Doug Hele with a steering head angle of 28 degrees to lessen any speed weave – together with an improved version of the 8” front brake with wider linings. This brake was better than the one before, although still far from ideal even for the soft-tune version of the 650.
The 650 twins also received a significant series of engine upgrades for 1966, which turned out to be the Thunderbird’s swansong year. The motor’s mass was reduced by 2.5lb with the introduction of a new crank and flywheel. Unlike the sports twins, the 6T wasn’t afflicted with Thruxton cams and high comp pistons so once again it escaped the effects of nasty high-rev vibration. Words like ‘harsh’ and ‘highly strung’ might be applied to the T-Bird’s stablemates, but the 6T retained its relaxed attitude.
Cooling improved with greater oil capacity and the last 6T should be slightly less leaky than an earlier Bird, as the prone-to-seeping oil pressure warning widget was removed. Somehow, the 6T’s claimed power also snuck up during the 1960s, from 34bhp when introduced to 40 in its final incarnation. So the 1966 edition might just be the best bird of the bunch…
The Thunderbird certainly proved to be the best value all-rounder in the Triumph range so far as fleets were concerned, and thousands were delivered to various municipal departments. Designated the 6TW until 1964 and the 6TP thereafter, some of the police T-birds were the same spec as customer bikes but individual forces had different requirements; legshields, space for radio sets, fairings and so on. While initially the unit-construction police bikes were all black, from 1965 the Metropolitan Police switched to white livery.
Harry Woolridge, who worked for three decades at Meriden, recalled that the Met’s bikes had to be certified capable of surpassing 100mph, so each machine was speed-tested at MIRA. Some police machines were delivered with a different carb (a 389 Monobloc), wide-ratio gearbox and the Bonneville inlet cam, and similarly equipped Thunderbirds were also used by the IoM travelling marshals. But for traffic duty and navigating the city streets s, the 6T really needed to be tractable an nd dependable. That smooth flexibility makes it t ideally suited to today’s classic riders, w ho probably aren’t so fussed about its abilitya to hit the ton…
Which brings us to wha at you might pay for a 6T today, and that’s not much h more than a well turned out BSA A10 or an AMC sports 650, as it happens. Thunderbird prices range from £4000 for an unfaired model which needs some work, to a ready-toride bikini bike for £7000. Some chancer – I mean ‘optimistic trader’ – advertised an oddly
orange-coloured one for £11,500 recently, but that’s mad money. You could instead pay the £8k asking price for one of the initial 1963 editions, complete with its original bodywork and lots of history from its long-term owner. I’d probably haggle him down a bit; £7500 is about top dollar for an OTR example from a dealer with a threemonth warranty.
Or if you want one of the last of the line, an unfaired 1966 machine like our featured bike, Barnfields Classics are selling a restored example for £5500. Another ‘ran recently but needs recommissioning’ 1964 6T sold for £5737 at auction last year, while a dusty 1965 bike, stored for two decades, fetched just £4000.
You’ll frequently find the final 1966 6Ts being overlooked at auctions – they don’t have the traditional styling of the older Birds and are overshadowed by their Trophy and Bonneville siblings. Quite a few get turned into Trophy clones with high pipes and wide bars, which doesn’t make them worth any more money. You should get a good, late Thunderbird for £5000 – less than half the price of its pre-unit counterpart.
That was part of the attraction for Steve in Australia, whose bike we see here. A long-term motorcyclist who took his bike test before he ever thought of driving a car, Steve was on the lookout for a practical classic a couple of years back.
‘I’m lucky enough to have a partner, Jennifer, who enjoys motorcycling as much as me,’ he explains. ‘I was after a usable classic that had enough torque for comfortable two-up riding, and the Triumph more than fits the bill.’
Steve’s been round the block with a wide variety of two-wheelers, ranging from BSA’s Bantam to a Suzuki Hayabusa through a 350 Douglas to a Rickman Honda. He’s owned a pre-unit Triumph before so felt comfortable with taking on a partially