1983 Triumph Bonneville

What the public didn’t see was the life-or-death, day-to-day struggles the workers and management of the Co-op were going through just trying to survive. There always seemed to be a salvation of some sort within reach, however, either through public or private funding. Undercapitalized such that they couldn’t even afford to produce the 1983 Triumph Bonnevilles that had been ordered by dealers, they were told by all the “experts” that funding would only be possible with a solid 5-year plan to turn things around. And new products were at the top of the list. On a shoestring, the resourceful boys at Triumph managed to cobble together the next-generation of Triumph Motorcycles, the Diana 900cc DOHC water-cooled twin that stole the NEC Motorcycle Show in 1983 in England. Alas, this potentially successful machine never reached production.

Triumph Motorcycles needed to do something for sure and in this, their last year in business, they really pulled out the stops. Considering how strapped for cash they were and how little they had to work with in terms of modern equipment and manpower (over 2/3 of the Meriden workforce had been laid off by this time), doing a radical redesign of the Bonneville’s entire top end and major parts of the bottom end was a daunting and ambitious undertaking. But again, those scrappy Brits at Meriden found a way.

The standard 1983 Triumph Bonneville T140ES soldiered on pretty much unchanged. The 1983 Triumph Bonneville TSS got a Brembo rear master cylinder and the swing arm was widened to accomodate a larger rear tire, a 5.10 X 16″, with a 3.25 X 19″ up front. Rear shocks the the TSX were Pailois with chrome springs and black bodies. Marzocchi shocks were used on all other models this year, with the TSS using Marzocchi’s top line Strada units with remote oil reservoirs. The TSX got polished fork sliders but the rest of the line got the black-out treatment. Morris alloy wheels were now fitted to every 1983 Triumph Bonneville with the exception of US-market T140s, which retained the wire wheels.

The Euro tank was used on all models except the TSX which sported a 3.6 US gal ‘peanut’ tank with hinged central fuel cap and only one petcock (with crossover tube). The wild new colorful striping packages were now peel-and-stick vinyl stickers, not painted-on stripes. Applied on tanks with compound-bent surfaces, wrinkles were common. The 1983 Triumph Bonneville T140ES got chromed fenders again, but all others were painted. The TSS could be painted all black with gold double pinstripes. Paint colors for 1983 were more plentiful than ever in Triumph’s history with no less than 8 color combos for the UK and 8 for the US markets.

1983 Triumph Bonneville Executive

The 1983 Triumph Bonneville Executive made a fairly decent touring bike.

The 1983 Triumph Bonneville Executive was Triumph's premium bike.  It was meant to be a touring bike with fairing, panniers (saddlebags) and top box.  A 'King & Queen'-style seat was added for greater comfort over long hauls.  Later bikes came standard with dual front disc brakes.

1983 Triumph Bonneville TSX

The 1983 Triumph Bonneville TSX was intended to convey the 'West Coast Low-Rider' look.  Norton had been slapping different bodywork on the same old Commandos to create whole new bikes again and again.  Triumph was starting to catch on.  The TSX was an excellent example of the concept, because underneath its a nearly-stock 1983 Triumph Bonneville ES (electric start).  Triumph added a trick new paintjob, available in red or black, painted the fenders (other Bonnies had polished stainless fenders), added a cool set of pipes and fit a 5.10 X 16" Morris alloy wheel and tire on the back.  The TSX however, broke with the concept by actually making mechanical changes to the core machine by widening the rear swing arm to accommodate the wider tire, and by relocating the rear shock mounts to lower the chassis.  This angled the shocks more sharply which improved the looks.  All TSXs were based on the ES with electric start.  The shorty pipes had larger bores than the standard mufflers and so were louder, and improved performance slightly.  These were great looking bikes and they sold pretty well by Triumph standards.  After the poor sales the the 1979 T140D Bonneville Special, Triumph didn't want another dud.  The T140D was black, and while handsome, wasn't much of a head-turner.  This time designers made sure people would see the TSX, and they certainly did.  Orders for the TSX vastly outstripped Triumph's ability to build the bikes.  This sounds impressive, but these were very low numbers by most peoples' standards, and they still couldn't fill the orders.  

The 1983 Triumph Bonneville TSX painted in black.

1983 Triumph Bonneville TSS

As close as they were to the brink of extinction, the optimists at the Meriden Co-operative still believed it could be turned around, and the only way was through product. Nothing like an entirely new DOHC 4-cylinder or the like, but maybe a whole new 4-valve (per cylinder) head for the antiquated 1983 Triumph Bonneville was within reach. As strange as this sounds today, it probably made sense at the beginning of 1983.  Because the bike that would result from it solved two of Triumph’s biggest challenges in the marketplace: power and smoothness.

With their credit rating falling and the company running out of money, the determined team cobbled together two new “Specials” for the 1983 model year: The Bonneville TSX (another highly-styled appearance package) and the radical 1983 Triumph Bonneville TSS with 8 valves in the head (4 valves per cylinder).

Sadly even the radical TSS was a case of “too little too late” and it wasn’t possible to fully develop the bike as it needed to be a real first-class contender. But this new engine showed promise to pump some performance back into the aging 1983 Triumph Bonneville with a claimed 59 hp and a top speed of 125 mph.

The TSS was essentially a standard 1983 Triumph Bonneville T140ES with the addition of an entirely alloy cylinder and head which was based on the old Westlake 8-valve racing heads of the 1960s, with some technical help from Westlake and a license to produce them. The engine cases were standard T140ES, with an all new crank turning on higher-spec bearings, supposedly able to spin to 10,000 rpm. This one-piece forging had larger diameter 1.875″ big-end journals and thicker webs. Interestingly, the bore centers were spread apart by 1/2″ so offset connecting rods were used to make up the difference. The top end cooling fins were of a higher pitch than traditional Bonnies, and more square. Compression ratio was 9.5:1 and the conventional head gasket was replaced with 2 Cross-rings that seated in the head. There were still 10 head bolts, but the outer 4 were now studs running all the way through the cylinder block to the crankcase. The 4 valves per cylinder were now more steeply angled than before (the valves in a traditional Triumph 650/750 twin are at a 90-degree angle relative to each other; the TSS valves were at 60 degrees, which allows for better flow) and were actuated by forked rocker arms, each operating 2 valves apiece. The head was cast such that the rocker shafts no longer rode in detachable rocker boxes, instead they were supported by beefy bosses cast right into the head. This is an improvement that would have benefited the traditional Triumph Bonneville engine greatly, since the detachable rocker boxes are under such rocking forces, stresses while torquing down the head (pre-1971) and the were prone to leaking. The entire top cover could be removed on the TSS revealing the valve gear and making it much easier to adjust the valve clearances.

The 1983 Triumph Bonneville TSS was a last-ditch attempt by Triumph Motorcycles to modernize the venerable vertical twin. A new all-alloy top end with 4 valves per cylinder with a new crank and rods netted 59 hp. Designed with help from Westlake, who was supposed to also be the supplier. However, it turned out that Westlake was also strapped for cash and would often place Triumph’s work aside to take cash jobs! As the result, there were never enough TSS 8-valve heads to meet demand. Also, the Westlake heads proved to be porous and leaked oil. Ultimately, Triumph had to take over production of the top ends for themselves, just to guarantee quality and supply. These bikes were supposed to be very fast. I rode with this bike (pictured above) on the 2011 Quail Ride through the Carmel Hills in Central California. Unfortunately, it wasn’t running right that day and was idling very high. But a beautiful and historically-important motorcycle nonetheless. And he rides it!! How cool is that?

In the end, one must wonder if they knew how close to the end it was, otherwise why come out with a radical new bike? They must have made themselves believe that the 1983 Triumph Bonneville TSS would do the trick, get them back into the game. In the end, hot rodding a 40-year-old pushrod twin would have never worked in the face of technologically-advanced new 3-, 4- and even 6-cylinder bikes pouring out of Japan. The same year Triumph introduced its quirky TSS, Honda came out with its 750 Interceptor with state-of-the-art DOHC, 16-valve 90-degree V-4 engine that was fast, smooth, sexy and well put together. The Interceptor ushered in a whole new age of race-inspired sport bikes that would certainly have woefully outclassed the ancient 1983 Triumph Bonneville, no matter how it was modified. Times had changed, progressed moved on. The Triumph Bonneville, once the fastest production motorcycle in the world, was now an outdated, irrelevant relic of the past.

1983 Triumph Bonneville Specifications

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1983 Triumph Bonneville Books

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