TRIUMPH TSS
This time, Ace Tester Miles becomes acquainted with the last of the line, the ultimate evolution of the original Triumph Bonneville
Study the timeline of a popular motorcycle and it generally follows a familiar arc. As a brand new design there will be innovations and features that should, in theory, further stretch the boundaries of motorcycling; usually performance. Subsequent models will include modifications to overcome shortfalls in the original design that are only exposed by these early purchasers acting as high mileage test riders. The machines often get heavier and slower as the market or legislature demands more complex gadgetry, with the last version bearing little more than a passing resemblance to the bright vision of the original designer.
Yet the later bike is likely to be the most fully developed and reliable example of the model. History is littered with such stories. Think of the first Z1 variants from Kawasaki, for example; the fastest, purest concepts. Later Z900s then Z1000s were heavier and slower although less thirsty, more reliable and far better in the handling and braking stakes. Collectors, of course, desire the early model, riders perhaps, the latter.
It was just the same with Triumph’s venerable twin, the Bonneville. The pre-unit machines were lithe and nimble as well as astonishingly pretty, but far from fault-free. As the years passed, the factory unified the engine and gearbox, made a serious attempt at keeping the oil inside the motor and uprated the brakes, electrics and gearing. The resultant T140 range is dynamically far superior to the earlier machines, but is somehow left wanting. It lacks the rawness, the purity of the earlier bike. Desirability and hence prices reflect this. The T140 is possibly the cheapest way into classic British biking, whereas the 1969 pre-unit Bonnie is hedge fund money.
Have some sympathy then for the workers’ co-operative at Meriden. Having survived the sit-in and somehow still managing to produce the Bonneville, they understood that the modern customer would no longer tolerate an underpowered, vibratory twin that required a firm boot to start. By the early 1980s Triumph were selling their aged design at a premium price, trying to woo the potential customer away from cheaper, faster, more modern designs from their competitors. Strangled by debt, the factory still managed to put out some innovative designs, albeit on a shoestring budget – the rubber mounted anti-vibration twin, the custom-styled TSX and possibly the most ambitious, a high performance eight-valve road burner, the TSS.
Four valves per cylinder on a Triumph twin were nothing new, of course. The previous decade had seen the racing engineering firm Nourish commissioned to build an eightvalve head for the T140. Smaller valves enable the fitting of a central spark plug, ensuring a better burn from the explosive mixture. Four small valves weigh less than two large ones, permitting a significantly higher rev ceiling, the holy grail of racing power. If one were to design a performance engine from scratch today, there is little chance it would be anything other than a multi-valve design. Cash-strapped Meriden knew this too, but found themselves having to tread the uneasy line between cost-effective modernisation without upsetting their loyal, if dwindling, existing customer base.
I spoke with a Nottinghamshire-based dealer who enjoyed a close relationship with the factory at the time. ‘ They (the factory) talked with Nourish who informed them that the modified head currently in production would be quite suitable for road use with no other modifications. However, the engine designer, Brian Jones, wanted to present the customer with a thoroughly updated design, future-proofing the concept for subsequent developments and changing the engine styling to something more akin to the closefinned 500cc engines of yore.
‘Instead of just using the Nourish head under license, Jones designed a completely
new, restyled top end, with matching barrels. He also increased the space between the two cylinders, possibly to allow for future capacity hikes as well as improving cooling on this higher revving engine. This necessitated further investment in different conrods and a totally redesigned crankshaft’.
While all of these changes would undoubtedly bring the venerable Triumph more up to date, it involved the factory in huge extra expense they could little afford. With hindsight, it’s easy to point the finger at poor decision making by ignoring the cheap and easy route, but they must have reasoned that the buying public wouldn’t suddenly switch to Triumphs in droves simply because the factory were now using a decade-old, third party cylinder head. If they could get it right, the uprated, stronger, more attractive and powerful eight-valver could form the basis of the next generation Triumph twins.
Quality control from both parts suppliers and, sadly, the production line itself, did the new machine few favours. Rumours of porosity in the heads began to circulate, as well as braking problems in wet weather. The dealer recalls; ‘We sold around six of them, with three never to be seen again; presumably they were OK. The others came back to us for warranty repairs, but we had one that never worked properly. The customer’s old, worn out T140 was significantly quicker than his shiny new TSS! We ended up refunding his money.’
The machine we see here is a UK model, fitted with Amal Mk2 carburettors rather than the leaner burning Bing units fitted to export markets. It has been restored and is almost factory correct. By the early 1980s, Triumph were casting the net far and wide in order to source parts for their models. Again, the cynical response would be that they had used up all their credit with UK manufacturers and had to go abroad to obtain parts. The reality is more likely to be the dearth of British suppliers – who were they expected to sell their products to? Only Triumph survived by then and in highly emaciated form.
Meriden looked chiefly to Italy for cycle parts and the TSS was equipped with fork parts, trendy Marzocchi piggyback shock absorbers, Paoli fuel taps and a rather pretty tank, all hailing from Italy. French Veglia instruments promised high-end of the scale excitement from the new engine. Lucas still provided most of the electrics, including electronic ignition, and the later variants of all Triumphs came equipped with the allimportant electric start.
The stylists did a great job, too. The TSS manages to look like a fresh version of an old favourite, with Jones’ engine changes distancing the TSS from the old-fashioned look of the traditional T140. Triple disc brakes were spot on trend and, while the eight-valve machine couldn’t expect to compete with the best of the Japanese on pure performance, providing it was fast and reliable and assuming they priced it correctly, there was a chance it could carry them forward into the future.
On paper they claimed 58bhp, about a 20% hike on the standard model, coupled to a light weight of 182kg; the resultant power to weight ratio compared favourably to much of the competition. The price, however, proved a major obstacle. At £2399 in 1983, the TSS cost virtually the same as Kawasaki’s new Z1100, one of the world’s fastest motorcycles and something to which a pushrod 750 twin, however clever, couldn’t possibly compare. Only 438 Triumph T140W TSS bikes were built before the co-op eventually went into voluntary liquidation. This rarity, plus the novelty of being simultaneously the first of a new model and the last of a long and illustrious line, have helped make it extremely collectable today.
In many ways, riding the TSS is just like riding a standard late-model Bonneville, only better. The electric start was both a surprise and most welcome, the twin fired instantly hot or cold. The handling and brakes were as sure-footed as only a relatively lightweight, pedigree motorcycle can be. Well-designed lighter bikes will always feel easier to ride than a complex (…read Japanese) behemoth. Even the riding position is neutral; an existing Triumph owner would find few surprises here.
What will surprise them, however, is the performance. There’s lots of it. Grunty and responsive at low revs, it’s everything you’d expect from Meriden’s finest. The difference
is found when the throttle cables are stretched. The eight-valve bike leaps forward, spinning up hard and quickly, almost like a four cylinder bike. This one major change transforms the Triumph from the former – nice but a bit old fashioned – into a genuine road burner. The press bike was timed at 125mph, make of that what you will, but there is little doubt of the potency out on the road. It’s smoother, too, the redesigned, larger main bearing crank helping keep vibes to a minimum. In fact, it’s hard to believe the engine beneath you is merely an updated version of a pushrod twin with a lineage going back nearly eighty years.
If only the factory had sold enough units to allow the customer development any new machine requires they might just have pulled it off, too. Plans for 1984 included fitting the new engine into the experimental AV frame. In truth, the TSS is so smooth it hardly needed it, but such is progress.
The TSS, though not without its rough edges, is a fascinating glimpse into what Meriden Triumph might have gone on to do given enough time and cashflow. It feels a generation ahead of the standard T140 in both smoothness and performance, but we would have to wait until John Bloor’s emergent new Triumph business for the world-beaters to truly arrive. So the pushrod eight-valve twin remains a footnote in history, but a fascinating one at that.