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Yamaha v British 650 Twins!

The Honda CB750 was one thing, but Yamaha arguably delivered an even more damaging blow to British egos in 1968 by unveiling a new 650cc parallel twin..............

Its July 2014 and Rod Ker time travels......back to the 1970's once again!



1972 Yamaha XS2 650

A 1972 Yamaha XS2 650 - This example is a rare and one owner UK machine!

After a six year interlude devoted mainly to the manufacture of killing machines, British motorcycle factories resumed production as soon as the wartime dust settled. The world wanted to get moving again, and Triumph, BSA, Norton, Velocette and many others were ideally placed to provide the required two-wheeled transport. As in the car industry, shortage of materials was a problem, but at least bikes didn’t use acres of sheet steel, so it wasn’t long before BSA could justifiably boast about being the largest motorcycle manufacturer on the planet.

Here in the homeland, we steadily became richer (or at least, less poor) in the 1950s, and the decade signed off with record registration figures. We’d never had it so good, as the Prime Minister told us, and things could only get better. Furthermore, British was best, so it was brandy and cigars in the boardroom, a quick chorus of Rule Britannia, and business as usual.

Or was it? Not everyone in Blighty shared this blinkered optimism. Edward Turner, the man who had put Triumph motorcycles back on the map in the 1930s by designing and marketing the Speed Twin so brilliantly, visited the Far East on a fact-finding mission not long before he retired. He realised that the nascent Japanese industry was soon going to be a serious threat to the UK, and unless the Brits acted promptly, there would be trouble.

It’s easy to be wise in hindsight, of course, but while everything seemed to be superficially hunky dory in the 1960s, largely due to booming US exports, the rot had well and truly set in beneath the surface. Nearing the end of the decade, Honda dropped a bombshell in the form of the CB750, an all-new four-cylinder, ohc marvel with front disc brake and guaranteed performance, reliability and oil-tightness. So much for the naïve belief that the Japanese would never be able to make anything other than small capacity bikes.

And what did the British have to fight back? Well, there was the Norton Commando 750, basically an overstressed, twenty year-old engine housed in a chassis that absorbed vibration instead of tackling its root cause. From another part of the Midlands came the Triumph Trident and its BSA Rocket 3 clone, which shared most of their DNA with the even more ancient Speed Twin, and&ldots; Not much else, really, apart from the Bonneville 650, of course, also based on 1937 technology. So, as the 1970s dawned it took a very strong pair of rose tints to entertain the notion that the UK motorcycle industry had a secure future.

1972 Triumph TR6 Tiger 650

 1972 Triumph TR6 Tiger 650 - a very low mileage example

The Honda CB750 was one thing, but Yamaha arguably delivered an even more damaging blow to British egos in 1968 by unveiling a new 650cc parallel twin that in the cold light of day was better than the ones made by Triumph, BSA, Norton et al. What a cheek! Still, those who believe that the Japanese only copied will be relieved to know that the engine was actually less new than it appeared to be, being based on the Hosk 650 twin, which was in turn a development of the German Horex 500 of the 1950s. Hosk had later become part of Showa, and Showa was taken over by Yamaha in 1960.

Yamaha’s interloper wasn’t generally available until 1970, initially called XS1, but often referred to as the XS-650 because that’s what it said on the sidepanels. Not that we were likely to see one, because UK imports only began in 1972, by which time the XS1-B had been supplanted by the XS2.

The big news here was an electric starter, which guaranteed that even nine stone weaklings could fire up the engine at the press of a button. To ease the task, a valve lifter was fitted at first, but later models had a more powerful motor that was man enough to spin the engine over compression. Once running, the twin had a slightly clanky, rumbly engine, but this was pretty well drowned out by a surprisingly loud exhaust note. In a blind test (not recommended), most riders would have assumed they were aboard one of Britain’s finest.

Even without opening your eyes, the illusion might not have lasted long, because the Yamaha engine generally didn’t leak oil or petrol and therefore didn’t have that distinctive bouquet when it warmed up. It was also generally bulletproof, so there was no need to carry a 345-piece toolkit, a spare set of main bearings or a supply of rocker box covers. While there was nothing particularly innovative about the 653cc (or 654cc, depending which spec sheet you believed) twin, it was a very solid bit of engineering. Everything that turned did so in either ball or needle-roller bearings fed oil at low-pressure, rather than bushes or plain bearings that needed a constant high-pressure supply to survive. The only downside was a bit of extra noise, but that mattered little in the early Seventies, long before whisper quietness was required by legislation.

In engineering terms the closest rival was Laverda’s 750 twin, launched at around the same time, but that was hugely expensive and difficult to find, even supposing the funds were available. And to return to the subject of ‘copying’, it has to be pointed out that the Italian twin was uncomfortably close to an expanded version of first-generation Hondas of the CB72 ilk.

In 1972 the XS2’s direct competitors were the Bonneville and (for a very short time!) BSA 650 A65. Interestingly, the latter had exactly the same over-square, 75 x 74mm cylinder dimensions as the Yamaha – quite a novelty for the British, as most engines had long-stroke configurations, which tended to limit rpm ceilings, which in turn limited power outputs. The XS2 was credited with 53bhp at 7000rpm, while the contemporary Beesa Lightning boasted another horsepower at an alarming 7250rpm.

Yamaha XS650B

Yamaha XS650B - a lovely example!

Despite appearances, the ‘power egg’ unit construction A65 was a direct descendent of the A10 (some would say an inferior one), and whether it was mechanically safe at such speeds, it certainly didn’t sound or feel very happy. At up to about 3000 the engine was smooth enough, but vibration of the knuckle-shattering variety came flooding in long before the power peak, to the extent that most owners would back off for fear of getting a pushrod up their nose. In contrast, the Yamaha twin would shrug off the sort of treatment that would overwhelm the BSA warranty department.

Meanwhile, the long-running Bonneville still had the same basic 650 engine, essentially a unitary construction variation of the 1937 twin, but had gained a completely new chassis, based on a large-diameter spine doubling as an oil tank. This was slightly ironic, as by the late 1960’s the once wild handling had been tamed. A new engine should perhaps have been more of a priority, but the muddled management had decreed that BSA and Triumph big twins would have this new frame, necessary or not.

BSA died after only a few re-framed 650s had been produced, but Triumph was stuck with it, and the response from customers was less than enthusiastic. The seat was too high, the petrol tank was too shapeless. Americans disliked the new look so much that they demanded changes, which can only have helped Yamaha get a foothold in a crucial market.

It didn’t take long to discover that the XS engine could be enlarged and tuned without causing reliability issues. Sidecar motocrossers and flat track racers found that the twin could be expanded to almost a litre, with young Keny Roberts being one satisfied user. In the UK, Tony Hall at Halco Tuning established himself as our chief XS guru. 750cc was the first step on the go-faster trail, good for at least 10bhp more, but an 840cc conversion was the bees’ proverbials for true connoisseurs.

Apart from increased displacement, a popular modification was to re-phase the crankshaft by pressing it apart and reassembling with the throws spaced by 90 degrees . Obviously, this also involved a new camshaft and rearranged ignition, but the end result was a smoother, less stressed engine. It’s ironic that British manufacturers had experimented with the same concept years earlier and decided not to put it into production. If further proof that it worked were needed, look no further than the current Triumph range, which includes huge vertical twins with staggered firing intervals (although note that these do have additional balance shafts to quell the shakes).

Yamaha’s original aim with the 650 was to muscle in on the US market segment dominated by ‘lightweight’ Brit bikes, leaving the heavyweight sector to Harley. The UK situation was rather different, and it seems that after some unflattering press exposure the importer didn’t really expect many punters to desert their beloved Beesas and Trumpets to buy a Japanese version of the same thing, no matter whether it was fundamentally better. Incidentally, the UK list price of £653 (£1 per cc?) was about fifty quid more than the homegrown opposition.

1970 Honda CB750

 The 1970 Honda CB750 - This example was a rare and one owner UK machine!

It has to be said that Yamaha did some strange things in the 1970s. While the XS2 was unquestionably a fine piece of engineering, they then decided to launch the TX750, which was unquestionably a fine piece of something else. This was another vertical twin, but it had absolutely nothing else in common with the 650. Instead of rolling element bearings throughout it had car-type plain bearings with high-pressure lubrication. The real novelty, though, was Omni-Phase balancers, basically a pair of chain-driven rotating weights that cancelled out the twin’s imbalance. Roadtesters liked the TX750 (‘The twin that feels like a four&ldots;’), but it wasn’t long before the engine developed a disastrous reliability record, caused by the very feature that made it so smooth!

Then there was the TX500, another balance-shaft twin, but again with another completely different engine. Double overhead cams operating four valves per pot was the headline feature. Despite great promise, the 500 also failed to measure up to expectations. Even with all that high-tech, it wasn’t any faster than a Triumph Daytona. Not that buyers were able to buy one of those after the Meriden factory sit-in effectively ended production of the smaller twins, although a few stockpiled bikes were liberated before Triumph became a workers’ co-op.

When the TX500 and TX750 appeared, it seemed logical for the XS2 to become the TX650 in some markets. The troublesome 750 was never officially available in the UK, anyway (probably luckily), so while we did briefly have the TX500, this quickly turned into the XS500B and XS500C. Meanwhile, the XS2 never sold well in Britain and had virtually been forgotten after a couple of years. Rather than move on (or perhaps make another mistake like the TX750?) Yamaha decided to update the 650. To this end, the new European R&D centre based in the Netherlands brought in expertise from the former enemy, in the guise of racer and ex-Triumph test pilot, Percy Tait.

The result of his labour was seen in 1975 as the XS650B. Outwardly, the obvious changes were ‘Blitish’ styling, alloy spoked wheels, twin front calipers behind the fork legs and a massive pair of silencers. Under the new clothes, the engine was little changed, but the frame benefited from extra gusseting, a longer wheelbase and altered geometry. Ready to rumble, the bike weighed about 15kg more, but the handling was definitely more predictable, if not perfect.

At a UK price of £875 the updated twin wasn’t particularly cheap for what it did. Test reports quoted a top whack of only just over 100mph, which on the face of it was no better than the Triumph Thunderbird 650 launched 25 years earlier! You could buy a lot more speed for your money elsewhere, eg. £770 for a Suzuki GT550 triple, or £979 for a Honda CB750 four, with hefty discounts available. Worse was to come for Yamaha, because the second half of the Seventies saw a host of new models being launched by the opposition. Who wanted a throwback Japanese twin? Most people preferred the real thing, warts and all, so it was amusing that while Suzondahaki tried to out-super themselves, business was booming at Triumph, resulting in the Bonneville and its single carb Tiger brother being the top-selling 750 by 1979!

Having left the XS650 alone for several years, Yamaha suddenly had a good idea and launched the Custom, aka Special Edition, or XS650S. Listed at £1420 in the UK, this was a very different machine with a fat 16-inch rear tyre, burbly silencers and a look that seemed to please everyone. Despite the chassis changes and cow-horn handlebars, the handling wasn’t too bad, and the engine had just the right power characteristics for a cruiser. After 1980 the 650 still had plenty of fans, particularly elsewhere in Europe, so it was a sad day when production finished with a swansong Heritage edition. Even then, a few XS650s were still lurking in the US dealer network until the second half of the decade, by which time motorcycles and motorcyclists were a completely different breed to the ones who first bought into the Japanese parallel twin back in 1969.

The TX750 may have been a white elephant, but Yamaha’s V-twins for the 1980s were (mostly) very successful, so there was no logical reason to keep the old stager XS650 in the range. Once officially terminated, a long time before it was seen as anything worth bothering about, so prices were modest. They still are compared with many other bikes of the same era, but this might not be the case in a few years. The new wave of classic customisers are snapping up tatty 650s that had spent decades unwanted, so you’re unlikely to find anything remotely usable for under £1000. Genuinely unmolested standard examples like the one seen here are very rare – rarer than the British opposition, in fact, so don’t expect to find any bargains.

For restorers the bad news is that parts are hard to find, although there is some crossover with other models of the same vintage. Just as it was forty years ago, the good news is that the engine shares one quality with its British rivals by being rebuildable, at a price. Money well spent, though, because a properly sorted XS2 or XS650 has great charm and character, as even a Triumph or BSA owner would have to admit!

By Rod Ker, July 2014
Photos and text are copyright Classic Bikes Ltd. unless otherwise noted.
Did you enjoy reading this? Please e-mail us your views to rod@classicbikes.co.uk


INDEX & LINKS to other articles (for more of the same);


- Kawasaki Z1-Z900 "Kawasaki's ‘New York Steak’ prototypes disguised as Honda CB750s were plying the roads of America by 1971, clocking up big mileages to make sure that everything was right first time.

- Class of '76: Laverda Jota v Kawasaki Z900

- Kawasaki 500 Triples. "If Hannibal Lecter practised dentistry, this is the sort of noise that would be coming from his surgery"!

- L-Plate 250s "Life was so simple for fledgling bikers back in the 1970s. Anyone capable of walking as far as the local No-Star dealer without tripping over his flares could buy a motorcycle, slap on a pair of L-plates, and wobble off into the traffic".

- Honda CBX1000 "If you don't know what a Phantom jet fighter sounds like, buy a Honda CBX and have a fiddle with the exhaust system"!