Yamaha Motorcycles (1953 - 2000)
Posted by Howard Trott on Thursday, December 24, 2015 Under: Japanese Motorcycles
YAMAHA Japan 1953 -
Torakusu Yamaha, whose name graces the sides of millions of motorcycles did not as far as I know ride one himself. In fact as he died in 1916, he may never have even seen a motorcycle, for which an explanation is required.
Yamaha was born in Nagasaki in 1851 and was first apprenticed to a clock maker, then to a manufacturer of medical equipment. He moved to Hamamatsu in 1883, then working as a self-employed engineer where he was asked to repair the organ at the local primary school. Yamaha evidently found this interesting as he decided to go into the musical instrument business himself. Nippon Gakki it was called and it thrived and was soon a major force in the market, which is why the Yamaha logo to this day consists of three tuning forks. But after Yamaha's death the company acquired an apparently dictatorial head named Chiymanu Amano, who was present during a number of strikes, not to mention the Kano earthquake of 1923. Order was restored by Kaichi Kawakami, who took over as president in 1926. His team building approach paid dividends and Nippon Gakki recovered, though during the war production of musical instruments was taken over by military work.
In 1948, sufficient normality was restored to allow for the manufacture of instruments to begin once more, though only two years later Kawakami passed the presidency to his son Genichi. One of his first acts as president was to utilize the wartime machinery which was lying idle, and one of the best uses was to build a small motorcycle for Japan's rapidly growing home market. With no experience of motorcycles, the company sensibly based its design on an existing one, namely the DKW RT125, which was the same DKW copied by BSA for the Bantam and Harley-Davidson for the Hummer, though there were others.
Nippon Gakki could afford to take its time perfecting the new motorcycle while building a brand new factory for it at Hamamatsu. And the name of the new motorcycle division ? In honour of the company's founder, it would be 'Yamaha'. That first machine, the 125cc YA1, did much for Yamaha's image by winning national races, and by the end of 1955 the company was building 200 a month.
Yamaha YA1 125cc
A larger 175cc version, still DKW based went on sale for 1956 and the YA series continued until the early 1970's. A 250 was the next step, and the obvious thing was to base it on an existing bike. The DKW 250 was rejected as being a single, and the Adler MB250 twin was bought instead. But once it was there, the design head considered their own 250 could do better. This was agreed, and Yamaha's YD1 was the result, sharing nothing with the Alder apart from basic layout and dimensions. A successful road motorcycle with a period pressed steel frame, it gave 17bhp.
Encouraged by its early successes, the company built a works racing version of the YD1, with the lighter, stronger tubular frame and even a short-stroke version of the motor. If was rewarded with a 1-2-3 in the Asama races in 1957, plus first and second in the 125cc race. Rival Honda had been conclusively beaten, and orders for the YD1 began to flow in. It is illuminating that so early on Yamaha had discovered the sales advantage that competition success could bring. Maybe this was why racing of all kinds has been so central to the company's activities ever since. Thus it was the first Japanese company to race in America, and plunged into European Grand Prix racing in 1961, scoring 7th in both 125 and 250 French GP's.
Racing Pays Off
So not long after its very first motorcycle went on sale, Yamaha was competitive in international racing. It had a slight headstart by taking over the Showa marque in 1959, whose 125cc racer was very fast and taught Yamaha much about disc valves. Unlike Honda, Yamaha at the time was still wedded to the two-stroke engine, whether for its racers or for simply commuter like the 80cc YG1, which was launched in the early sixties, but was still on sale as the YB100 30 years later. Although those early Japanese machines might look a little basic nowadays, they were quite advanced, the YB100 having automatic oiling and a disc value, plus an impressive 10bhp. Practical and reliable as well as nippy, it is no wonder they sold so well.
A twin-cylinder 100, the YL1 appeared in 1966, though this one only lasted five years. It could manage 70mph in standard guise and true to form Yamaha offered a race kit which nearly doubled the power. The YDS series were 250 twins, starting with the YDS1 in 1959, updated into the YDS2 in 1962 and YDS3 in 1964. All were 246cc piston-ported twins, with 28bhp at 8,000rpm. There was also a 305cc YM1. They eventually developed into the DS7, which itself was the immediate precursor of the long running RD-series. All these were road motorcycles, but just as important to Yamaha were the TD-series of off the shelf racers, starting with the 250cc TD1 in 1962, plus the 350cc TR-series, which was to become the liquid cooled TZ from 1969. That Yamaha was able to sell these racers was down to its own success.
In the late sixties the market for dual-purpose trail motorcycles was growing rapidly. Yamaha's importer persuaded the factory that what they needed was something close to the off-road ability of a Greeves or Bultaco, but with more civilized on-road manners. The DT1 was the result, and it was truly a new type of motorcycle. The 175cc two-stroke single was relatively comfortable and easy to ride. It was well silenced, had good lights and cruised happily at 60mph, yet it could also take to the dirt if you so wished. It was a hit and Yamaha's competitors soon came out with trail motorbikes of their own. So successful was the DT that a whole range of motorbikes grew up around it, from a DT50 to the relatively short lived DT400. It was said that like the luxury 4 x 4 vehicles, some of these trail motorbikes never got their tyres muddy, it was the suggestion of trailing that riders wanted.
Yamaha DT50
Although the DT opened up a new market, it wasn't that difficult for Yamaha to produce, being a two-stroke. The XS1, unveiled the following year, couldn't have been more different. It was the largest motorbike Yamaha had ever built, and it was a four-stroke. The basic idea was a sound one, take the highly popular British vertical-twin concept and update it to take up where Bonneville had left off. The XS certainly looked good on paper, being a 653cc twin with overhead cam, five-speed gearbox and electric start, plus Japanese reliability. It wasn't an instant success, for at the time Japanese manufacturers had yet to master the art of motorcycle road holding and handling, especially with the larger motorbikes.
Yamaha persevered and the revamped renamed XS650 was developed into quite a decent motorbike, acquiring a following of its own. The torquey engine was to prove adept at sidecar motocross and American flat-track racing. A measure of its eventual success is that Yamaha went on making it until the early 1980's. However one development didn't get that far. The TX750 was a bored out version of the 650, though as Triumph was finding out at the same time was really too much for an unbalanced vertical twin. Yamaha accepted this and designed a balancer system to counteract the vibration. It worked and the 750 was certainly smoother than the 650. Unfortunately the crankshaft-driven balancer sapped so much power that the TX was actually slower than the smaller motorbike, struggling to even reach 100mph. It was dropped just a few months after its launch.
Two-Stroke Days
Meanwhile Yamaha was having a happier time with what it knew best small two-strokes. The company had noted the huge success of Honda's Cub and like Suzuki came up with something very similar to meet it, though being a Yamaha it was a two-stroke. It came in V50 and V80 forms, both having reed-valves. The smaller had a two-speed automatic gearbox and the 79cc V80 was a three speeder. Naturally the two-stroke oil was mixed automatically, while drive was by enclosed chain. These two were later replaced by a four-stroke T50 and T80, both of which boasted the sophistication of shaft-drive. The earlier step-thrus offered no real advantage over the Honda, though that wasn't really the point, they gave Yamaha something to sell in this fiercely competitive market.
A more obvious class leader was the FS1 sports moped, which first appeared in 1972.With its disc-valved engine and motorcycle looks, the FS1E was the motorcycle for 16 year olds to be seen on in 1970's Britain. There were daring tales of 52, even 53mph on the right downhill stretch, when the author's Puch could barely manage 38mph on a good day. However, laws changed and these sports mopeds were restricted back to a maximum of 30mph. But it was still on sale 20 years later, in drum-braked or disc-braked forms.
If a sports moped rider survived the FS1E, he would often graduate to a DT175. Of all Yamaha's DT trail motorbike series, the 175 was possibly the best compromise. It had enough performance to be exciting, yet was light enough to take off-road easily, and much cheaper on fuel and insurance than the 250 and 400. No wonder it enjoyed a production run of 12 years ( 1973-1985 ). Among certain generations of riders, the letters 'FS1E' and 'DT' have a certain resonance, but none can compete with the magical 'RD'. RD stood for 'Race Developed' which in Yamaha's case had more than an element of truth in it, rooted as the company was in racing air-cooled two-stroke twins.
The RD series replaced the long running YDS in 1973, and its main advance was the use of reed-valve induction in place of conventional piston ports. Reed valves were not a new concept, and the basic idea is simple. Instead of relying on the passing piston to open and close off each port, the reed is a flap valve, sucked open by a vacuum under a rising piston, and closing as the piston descends. A key advantage is that ports are less compromised in shape and the power band is wider. But Yamaha's version used an innovation of its own, an extra transfer port above the inlet port, which drew in an extra helping of charge after the main one and improved scavenging as well. Perfect scavenging ( the evacuation of all exhaust gases from the cylinder to allow a full fresh charge to come in ) is the object of every two-stroke. In practical terms, this meant that the new RD250's power band now started at 4,000rpm instead of the previous 6,000rpm, with obvious benefits in rideability and fuel consumption.
Yamaha RD250LC
Yamaha demonstrated its faith in the new system by launching a whole range of RD's within a couple of months of one another. There was an RD125, RD200, RD250, and RD350, the two larger motorbikes had a six-speed gearbox. Those early Rd's looked very similar to the older YDS, but all had a comprehensive restyle in 1975, with squared off tank and seat and block style graphics that became the RD trademark. At the same time the RD125 and 200 acquired front disc brakes. A year later the RD350 became the RD400, due to an 8mm longer stroke, with 40bhp and a stronger bottom end to suit. After that there were just minor changes, though electronic ignition was a worthwhile advance in 1978. However the RD two-strokes for all their power, were simply unable to meet imminent U.S emissions limits, and the whole range was dropped in 1980.
XS & LC
It is odd that while Yamaha was producing such class leading and popular two-strokes, its four-strokes should still be relatively lacklustre. At first glance the XS500 twin announced in 1975 looked promising. Twin overhead camshafts, four valves per cylinder, and a balancer shaft to dampen the vibration. The all new engine produced a claimed 48bhp at 8,500rpm for a top speed of 109mph. Unfortunately the 500 was a weighty motorbike at over 200kg with disappointing acceleration and no real get up and go. The lighter simpler XS twins sold rather better. First was the XS360 of 1976, with single overhead cam and a 180 degree camshaft. An XS250 followed, while the 360 was later bored out to 399cc, all three motorbikes sharing the same 52.4mm stroke. The 400 lasted up to 1983, by which time it had a new backbone frame, twin overhead-cam cylinder head and monoshock rear suspension. It is still not remembered with quite the same affection as the RD.
There was a lot more anticipation when the XT500 trail motorbike was launched in 1977. Although rather heavy for serious off-road use, it echoed the DT in opening up a new market for trail motorbikes, in this case for big four-stroke singles which until then, Japanese manufacturers had ignored. The 499cc single overhead-cam engine looked simple in the extreme with just two valves, one carburettor and no electric start. Indeed, some thought this was the long awaited return of the simple, torquey big single. But it put out confusing messages, with the ground clearance, suspension travel and seat height of a proper off-roader, together with that 138kg mass.
Perhaps the SR500, a pure road motorbike, was a more honest use of the 499cc single. The engine was basically similar, but had larger valves and carburettor, and various parts strengthened to cope with high speed cruising. There was also decent 12-volt electrics and a disc front brake. Some were sold, but the SR wasn't really a modern BSA Gold Star. But in the same year that the XT appeared, Yamaha also came up with its first truly successful four-stroke. The XS750 was its belated Superbike competitor, and it was right first time. The 747cc dohc triple wasn't an out and out sportster, it was too heavy for that, and in any case the shaft-drive indicated that this was a motorbike with touring pretensions. Nor was it quite as fast, at 110mph as some of the other 750's but it was smooth and comfortable.
Performance was improved by an increase in capacity to 826cc in 1980, which took power up to 79bhp at 8,500rpm and a top speed of 125mph. And despite the weight it handled reasonably well, due to fully adjustable suspension at both ends. It was superseded by the four-cylinder XJ900 in 1983.
Despite its determination to break into the big four-stroke market, Yamaha's two-strokes were still doing well on the track, especially the twin-cylinder production racers. It won the 250cc World Championship four times in the 1970's ( 1970-73 ) and the 350 class in the following three years, plus two 125cc titles. The 500 class came Yamaha's way in 1973, then thanks to Kenny Roberts from 1978-80 as well. It was also developing a presence in off-road sport, winning motorcross GP's by the middle of the decade.
Kenny Roberts
Meanwhile although the air-cooled RD had been killed off by the U.S regulations, the motorbike had been so successful in Europe that Yamaha decided to launch a replacement aimed specifically at the Europeans. Still a two-stroke twin, the big news was that it was liquid cooled, which gave a more even running temperature and less noise. Although it looked completely different to the old RD, with its squared off shape giving way to a pleasing rounded form, the LC owed much to its predecessor. Reed-valve induction was still there, and the six-speed gearbox was familiar as well, but there was a new monoshock rear suspension and anti-vibration rubber mounting for the engine. Predictably the LC became the motorbike to have in Production Racing, winning 250 and 500 classes in its first TT. The only big development of the motorbike was the Yamaha Power Valve System which was unveiled in 1982. Its impressive 59bhp at 9,000rpm was made possible by a variable exhaust port, whose size and position changed automatically according to engine revs.
YPV's was also fitted to the ultimate RD, the 499cc V4 of 1984. The RD500LC was built to capitalize on Grand Prix success, but owed more to the LC than Kenny Roberts racer. The cleverly designed motor used two crankshafts and four carburettors, while the four YPV's valves were mechanically linked, operated by a single servo motor. Not for the faint hearted, this ultimate road going two-stroke could run up 135mph on its 80bhp. At the other end of the scale there were also liquid-cooled RD80's and RD125LC's, plus an air-cooled RD50.
At this time there were less exciting tiddlers from Hamamatsu as well. The SR500 had been followed by an SR250 and 125, though there were in a different mould being mild mannered commuters with custom styling. And all this time Yamaha was selling a full range of tiddlers, examples being the Passola 50 and scooter style 79cc Beluga.
It took Yamaha some time to folow the four-cylinder four-stroke route along which Japanese rivals had already ventured. After vertical twins and triples, its next attempt at an alternative big four-stroke was the TR1. Launched in late 1980, this was a 981cc roadster in European style. To appeal to its chosen market, the TR1 was relatively simple, the 75-degree V-twin had single overhead cams and two valves per cylinder, there was an enclosed chain-drive, vertically split crankcases and five-speed gearbox. The only newer elements were electronic advance for the ignition timing and monoshock rear suspension, which Yamaha had now been using for seven years. Alongside the TR1 was the basically similar but smaller engined 740cc Virago, with shaft-drive and custom styling. Both used steel backbone frames.
Fours & Fives
Yamaha was also selling a range of perfectly straightforward dohc fours. The XJ series began with the 550 before growing into the shaft-driven 650 and 750. None made a huge impact apart from the XJ650 Turbo, which along with Honda's CX Turbo marked a brief flirtation with turbos as an alternative to big engines, neither being successful. What did succeed was the bigger XJ900, which was unveiled in 1983. It was strong, torquey, fairly simple touring machine, with an 853cc dohc air-cooled four-cylinder engine and shaft-drive. The capacity was soo increased to 891cc and the FJ900 was quite a success, still selling 16 years on. In much the same mould was the FJ1100 of 1984, still an air-cooled shaft-driven four, but with far more power, monoshock rear suspension and an alloy frame. It could break the 150mph barrier and dawdle through town at minimal revs, winning the big FJ many friends. It also had a capacity increase in 1986 to 1188cc, as the FJ1200. There were more minor changes in 1988, but perhaps the most significant was the ABS option launched in 1991. Like the XJ900, the FJ is still in production.
Maybe this success with the bigger fours gave Yamaha more confidence with the similar ones. The Diversion 600 of 1991 certainly suggested this. There was nothing very radical about it, but it was a very good seller where the old XJ600 was not. Its 600cc four was a much simplified version of the Genesis concept, still with a slant forward block, but with air-cooling and two valves per cylinder. Despite, or perhaps because of the modest specification, the Diversion proved to be an excellent all rounder, which is what many people still want from a motorbike. Available in naked and half-faired forms, it was good valve and a deserved success. The 600cc class moved on so fast in the nineties that the Diversion was very much the budget option, the 95bhp Fazer 600 from 1998 being more contemporary.
Diversion 600
The V-Max on the other hand, could never be described as a sensible all rounder. Launched in 1985, it was an unashamed performance muscle machine, with sheer acceleration and speed, its single purpose goal. It looked like nothing else, with the surprisingly compact liquid-cooled 1198cc V4 of the Gold Wing style XVZ12, but with larger carburettors and valves, not to mention higher compression, stronger valve-springs and toughened bottom end. It is hardly surprising that the V-Max became something of a cult motorbike.
By the early 1980's, Yamaha had built successful four-stroke singles and tourers, but had yet to really take the sportbike market by storm. That came in 1985 with the FZ750. There was much new about the FZ, specifically its liquid-cooled 749cc four, with five valves per cylinder. Over a long development period, Yamaha engineers had experimented with six and even seven valve heads before settling on five as the best compromise between power and reliability. The cylinder-block was slanted forward at 45 degrees to lower the centre of gravity and allow good, straight inlet and exhaust ports, not to mention space for the four down-draught carburettors. It all added up to a very efficient and powerful engine that gave Yamaha class leadership for a while. It was folowed up in 1987 with the FZR1000 Genesis, whose main innovation was an alloy box section frame known as Deltabox. The latter was a big step forward, giving a lower seat height and far better handling than the steel framed FZ750. The engine was simply an enlarged 750, though with great attention paid to weight and space saving. Power was 135bhp, with a 165mph top speed.
New Sport, New Standards
Yamaha had not forgotten its smaller motorbikes, and still fovoured he two-stroke. The TZR125 of 1988 used a reed-valved two-stroke single together with the latest Deltabox frame. It came with or without a fairing, and was a great success. More intriguing was the TDR250, an attempt at mirroring the big TDM850 with a trail motorbike style but with road tyres and road performance. The twin-cylinder two-stroke gave an amazing 107mph maximum speed, and the TDR certainly provided an alternative to race replicas.
R1 (1999)
In the 1990's two motorbikes stand out. I've mentioned how the FZR series seemed t lose its way a little as the Thundercat and Thunderace. The motorbikes that changed all that were the R1 in 1998, and the R6 of 1999. The R1 is a milestone motorbike, setting new standards in the one-litre supersports class. It is lighter, smaller and more powerful than any of its rivals, and great play is made of the 'three figures' 150bhp, 177kg and 1,395mm shortest wheelbase. The R1 was the first of a new family of supersports motorbikes, including a 750cc R7 for superbike racing and a 599cc R6. With the R6, Yamaha had done it again. More power than any other 600, and it is marginally lighter than them all as well, its top speed being over 170mph. For a mere 600 it gives astonishing performance, and underlines the fact that Yamaha intended to hold tight to its sportsbike market leadership.
Torakusu Yamaha, whose name graces the sides of millions of motorcycles did not as far as I know ride one himself. In fact as he died in 1916, he may never have even seen a motorcycle, for which an explanation is required.
Yamaha was born in Nagasaki in 1851 and was first apprenticed to a clock maker, then to a manufacturer of medical equipment. He moved to Hamamatsu in 1883, then working as a self-employed engineer where he was asked to repair the organ at the local primary school. Yamaha evidently found this interesting as he decided to go into the musical instrument business himself. Nippon Gakki it was called and it thrived and was soon a major force in the market, which is why the Yamaha logo to this day consists of three tuning forks. But after Yamaha's death the company acquired an apparently dictatorial head named Chiymanu Amano, who was present during a number of strikes, not to mention the Kano earthquake of 1923. Order was restored by Kaichi Kawakami, who took over as president in 1926. His team building approach paid dividends and Nippon Gakki recovered, though during the war production of musical instruments was taken over by military work.
In 1948, sufficient normality was restored to allow for the manufacture of instruments to begin once more, though only two years later Kawakami passed the presidency to his son Genichi. One of his first acts as president was to utilize the wartime machinery which was lying idle, and one of the best uses was to build a small motorcycle for Japan's rapidly growing home market. With no experience of motorcycles, the company sensibly based its design on an existing one, namely the DKW RT125, which was the same DKW copied by BSA for the Bantam and Harley-Davidson for the Hummer, though there were others.
Nippon Gakki could afford to take its time perfecting the new motorcycle while building a brand new factory for it at Hamamatsu. And the name of the new motorcycle division ? In honour of the company's founder, it would be 'Yamaha'. That first machine, the 125cc YA1, did much for Yamaha's image by winning national races, and by the end of 1955 the company was building 200 a month.
Yamaha YA1 125cc
A larger 175cc version, still DKW based went on sale for 1956 and the YA series continued until the early 1970's. A 250 was the next step, and the obvious thing was to base it on an existing bike. The DKW 250 was rejected as being a single, and the Adler MB250 twin was bought instead. But once it was there, the design head considered their own 250 could do better. This was agreed, and Yamaha's YD1 was the result, sharing nothing with the Alder apart from basic layout and dimensions. A successful road motorcycle with a period pressed steel frame, it gave 17bhp.
Encouraged by its early successes, the company built a works racing version of the YD1, with the lighter, stronger tubular frame and even a short-stroke version of the motor. If was rewarded with a 1-2-3 in the Asama races in 1957, plus first and second in the 125cc race. Rival Honda had been conclusively beaten, and orders for the YD1 began to flow in. It is illuminating that so early on Yamaha had discovered the sales advantage that competition success could bring. Maybe this was why racing of all kinds has been so central to the company's activities ever since. Thus it was the first Japanese company to race in America, and plunged into European Grand Prix racing in 1961, scoring 7th in both 125 and 250 French GP's.
Racing Pays Off
So not long after its very first motorcycle went on sale, Yamaha was competitive in international racing. It had a slight headstart by taking over the Showa marque in 1959, whose 125cc racer was very fast and taught Yamaha much about disc valves. Unlike Honda, Yamaha at the time was still wedded to the two-stroke engine, whether for its racers or for simply commuter like the 80cc YG1, which was launched in the early sixties, but was still on sale as the YB100 30 years later. Although those early Japanese machines might look a little basic nowadays, they were quite advanced, the YB100 having automatic oiling and a disc value, plus an impressive 10bhp. Practical and reliable as well as nippy, it is no wonder they sold so well.
A twin-cylinder 100, the YL1 appeared in 1966, though this one only lasted five years. It could manage 70mph in standard guise and true to form Yamaha offered a race kit which nearly doubled the power. The YDS series were 250 twins, starting with the YDS1 in 1959, updated into the YDS2 in 1962 and YDS3 in 1964. All were 246cc piston-ported twins, with 28bhp at 8,000rpm. There was also a 305cc YM1. They eventually developed into the DS7, which itself was the immediate precursor of the long running RD-series. All these were road motorcycles, but just as important to Yamaha were the TD-series of off the shelf racers, starting with the 250cc TD1 in 1962, plus the 350cc TR-series, which was to become the liquid cooled TZ from 1969. That Yamaha was able to sell these racers was down to its own success.
In the late sixties the market for dual-purpose trail motorcycles was growing rapidly. Yamaha's importer persuaded the factory that what they needed was something close to the off-road ability of a Greeves or Bultaco, but with more civilized on-road manners. The DT1 was the result, and it was truly a new type of motorcycle. The 175cc two-stroke single was relatively comfortable and easy to ride. It was well silenced, had good lights and cruised happily at 60mph, yet it could also take to the dirt if you so wished. It was a hit and Yamaha's competitors soon came out with trail motorbikes of their own. So successful was the DT that a whole range of motorbikes grew up around it, from a DT50 to the relatively short lived DT400. It was said that like the luxury 4 x 4 vehicles, some of these trail motorbikes never got their tyres muddy, it was the suggestion of trailing that riders wanted.
Yamaha DT50
Although the DT opened up a new market, it wasn't that difficult for Yamaha to produce, being a two-stroke. The XS1, unveiled the following year, couldn't have been more different. It was the largest motorbike Yamaha had ever built, and it was a four-stroke. The basic idea was a sound one, take the highly popular British vertical-twin concept and update it to take up where Bonneville had left off. The XS certainly looked good on paper, being a 653cc twin with overhead cam, five-speed gearbox and electric start, plus Japanese reliability. It wasn't an instant success, for at the time Japanese manufacturers had yet to master the art of motorcycle road holding and handling, especially with the larger motorbikes.
Yamaha persevered and the revamped renamed XS650 was developed into quite a decent motorbike, acquiring a following of its own. The torquey engine was to prove adept at sidecar motocross and American flat-track racing. A measure of its eventual success is that Yamaha went on making it until the early 1980's. However one development didn't get that far. The TX750 was a bored out version of the 650, though as Triumph was finding out at the same time was really too much for an unbalanced vertical twin. Yamaha accepted this and designed a balancer system to counteract the vibration. It worked and the 750 was certainly smoother than the 650. Unfortunately the crankshaft-driven balancer sapped so much power that the TX was actually slower than the smaller motorbike, struggling to even reach 100mph. It was dropped just a few months after its launch.
Two-Stroke Days
Meanwhile Yamaha was having a happier time with what it knew best small two-strokes. The company had noted the huge success of Honda's Cub and like Suzuki came up with something very similar to meet it, though being a Yamaha it was a two-stroke. It came in V50 and V80 forms, both having reed-valves. The smaller had a two-speed automatic gearbox and the 79cc V80 was a three speeder. Naturally the two-stroke oil was mixed automatically, while drive was by enclosed chain. These two were later replaced by a four-stroke T50 and T80, both of which boasted the sophistication of shaft-drive. The earlier step-thrus offered no real advantage over the Honda, though that wasn't really the point, they gave Yamaha something to sell in this fiercely competitive market.
A more obvious class leader was the FS1 sports moped, which first appeared in 1972.With its disc-valved engine and motorcycle looks, the FS1E was the motorcycle for 16 year olds to be seen on in 1970's Britain. There were daring tales of 52, even 53mph on the right downhill stretch, when the author's Puch could barely manage 38mph on a good day. However, laws changed and these sports mopeds were restricted back to a maximum of 30mph. But it was still on sale 20 years later, in drum-braked or disc-braked forms.
If a sports moped rider survived the FS1E, he would often graduate to a DT175. Of all Yamaha's DT trail motorbike series, the 175 was possibly the best compromise. It had enough performance to be exciting, yet was light enough to take off-road easily, and much cheaper on fuel and insurance than the 250 and 400. No wonder it enjoyed a production run of 12 years ( 1973-1985 ). Among certain generations of riders, the letters 'FS1E' and 'DT' have a certain resonance, but none can compete with the magical 'RD'. RD stood for 'Race Developed' which in Yamaha's case had more than an element of truth in it, rooted as the company was in racing air-cooled two-stroke twins.
The RD series replaced the long running YDS in 1973, and its main advance was the use of reed-valve induction in place of conventional piston ports. Reed valves were not a new concept, and the basic idea is simple. Instead of relying on the passing piston to open and close off each port, the reed is a flap valve, sucked open by a vacuum under a rising piston, and closing as the piston descends. A key advantage is that ports are less compromised in shape and the power band is wider. But Yamaha's version used an innovation of its own, an extra transfer port above the inlet port, which drew in an extra helping of charge after the main one and improved scavenging as well. Perfect scavenging ( the evacuation of all exhaust gases from the cylinder to allow a full fresh charge to come in ) is the object of every two-stroke. In practical terms, this meant that the new RD250's power band now started at 4,000rpm instead of the previous 6,000rpm, with obvious benefits in rideability and fuel consumption.
Yamaha RD250LC
Yamaha demonstrated its faith in the new system by launching a whole range of RD's within a couple of months of one another. There was an RD125, RD200, RD250, and RD350, the two larger motorbikes had a six-speed gearbox. Those early Rd's looked very similar to the older YDS, but all had a comprehensive restyle in 1975, with squared off tank and seat and block style graphics that became the RD trademark. At the same time the RD125 and 200 acquired front disc brakes. A year later the RD350 became the RD400, due to an 8mm longer stroke, with 40bhp and a stronger bottom end to suit. After that there were just minor changes, though electronic ignition was a worthwhile advance in 1978. However the RD two-strokes for all their power, were simply unable to meet imminent U.S emissions limits, and the whole range was dropped in 1980.
XS & LC
It is odd that while Yamaha was producing such class leading and popular two-strokes, its four-strokes should still be relatively lacklustre. At first glance the XS500 twin announced in 1975 looked promising. Twin overhead camshafts, four valves per cylinder, and a balancer shaft to dampen the vibration. The all new engine produced a claimed 48bhp at 8,500rpm for a top speed of 109mph. Unfortunately the 500 was a weighty motorbike at over 200kg with disappointing acceleration and no real get up and go. The lighter simpler XS twins sold rather better. First was the XS360 of 1976, with single overhead cam and a 180 degree camshaft. An XS250 followed, while the 360 was later bored out to 399cc, all three motorbikes sharing the same 52.4mm stroke. The 400 lasted up to 1983, by which time it had a new backbone frame, twin overhead-cam cylinder head and monoshock rear suspension. It is still not remembered with quite the same affection as the RD.
There was a lot more anticipation when the XT500 trail motorbike was launched in 1977. Although rather heavy for serious off-road use, it echoed the DT in opening up a new market for trail motorbikes, in this case for big four-stroke singles which until then, Japanese manufacturers had ignored. The 499cc single overhead-cam engine looked simple in the extreme with just two valves, one carburettor and no electric start. Indeed, some thought this was the long awaited return of the simple, torquey big single. But it put out confusing messages, with the ground clearance, suspension travel and seat height of a proper off-roader, together with that 138kg mass.
Perhaps the SR500, a pure road motorbike, was a more honest use of the 499cc single. The engine was basically similar, but had larger valves and carburettor, and various parts strengthened to cope with high speed cruising. There was also decent 12-volt electrics and a disc front brake. Some were sold, but the SR wasn't really a modern BSA Gold Star. But in the same year that the XT appeared, Yamaha also came up with its first truly successful four-stroke. The XS750 was its belated Superbike competitor, and it was right first time. The 747cc dohc triple wasn't an out and out sportster, it was too heavy for that, and in any case the shaft-drive indicated that this was a motorbike with touring pretensions. Nor was it quite as fast, at 110mph as some of the other 750's but it was smooth and comfortable.
Performance was improved by an increase in capacity to 826cc in 1980, which took power up to 79bhp at 8,500rpm and a top speed of 125mph. And despite the weight it handled reasonably well, due to fully adjustable suspension at both ends. It was superseded by the four-cylinder XJ900 in 1983.
Despite its determination to break into the big four-stroke market, Yamaha's two-strokes were still doing well on the track, especially the twin-cylinder production racers. It won the 250cc World Championship four times in the 1970's ( 1970-73 ) and the 350 class in the following three years, plus two 125cc titles. The 500 class came Yamaha's way in 1973, then thanks to Kenny Roberts from 1978-80 as well. It was also developing a presence in off-road sport, winning motorcross GP's by the middle of the decade.
Kenny Roberts
Meanwhile although the air-cooled RD had been killed off by the U.S regulations, the motorbike had been so successful in Europe that Yamaha decided to launch a replacement aimed specifically at the Europeans. Still a two-stroke twin, the big news was that it was liquid cooled, which gave a more even running temperature and less noise. Although it looked completely different to the old RD, with its squared off shape giving way to a pleasing rounded form, the LC owed much to its predecessor. Reed-valve induction was still there, and the six-speed gearbox was familiar as well, but there was a new monoshock rear suspension and anti-vibration rubber mounting for the engine. Predictably the LC became the motorbike to have in Production Racing, winning 250 and 500 classes in its first TT. The only big development of the motorbike was the Yamaha Power Valve System which was unveiled in 1982. Its impressive 59bhp at 9,000rpm was made possible by a variable exhaust port, whose size and position changed automatically according to engine revs.
YPV's was also fitted to the ultimate RD, the 499cc V4 of 1984. The RD500LC was built to capitalize on Grand Prix success, but owed more to the LC than Kenny Roberts racer. The cleverly designed motor used two crankshafts and four carburettors, while the four YPV's valves were mechanically linked, operated by a single servo motor. Not for the faint hearted, this ultimate road going two-stroke could run up 135mph on its 80bhp. At the other end of the scale there were also liquid-cooled RD80's and RD125LC's, plus an air-cooled RD50.
At this time there were less exciting tiddlers from Hamamatsu as well. The SR500 had been followed by an SR250 and 125, though there were in a different mould being mild mannered commuters with custom styling. And all this time Yamaha was selling a full range of tiddlers, examples being the Passola 50 and scooter style 79cc Beluga.
It took Yamaha some time to folow the four-cylinder four-stroke route along which Japanese rivals had already ventured. After vertical twins and triples, its next attempt at an alternative big four-stroke was the TR1. Launched in late 1980, this was a 981cc roadster in European style. To appeal to its chosen market, the TR1 was relatively simple, the 75-degree V-twin had single overhead cams and two valves per cylinder, there was an enclosed chain-drive, vertically split crankcases and five-speed gearbox. The only newer elements were electronic advance for the ignition timing and monoshock rear suspension, which Yamaha had now been using for seven years. Alongside the TR1 was the basically similar but smaller engined 740cc Virago, with shaft-drive and custom styling. Both used steel backbone frames.
Fours & Fives
Yamaha was also selling a range of perfectly straightforward dohc fours. The XJ series began with the 550 before growing into the shaft-driven 650 and 750. None made a huge impact apart from the XJ650 Turbo, which along with Honda's CX Turbo marked a brief flirtation with turbos as an alternative to big engines, neither being successful. What did succeed was the bigger XJ900, which was unveiled in 1983. It was strong, torquey, fairly simple touring machine, with an 853cc dohc air-cooled four-cylinder engine and shaft-drive. The capacity was soo increased to 891cc and the FJ900 was quite a success, still selling 16 years on. In much the same mould was the FJ1100 of 1984, still an air-cooled shaft-driven four, but with far more power, monoshock rear suspension and an alloy frame. It could break the 150mph barrier and dawdle through town at minimal revs, winning the big FJ many friends. It also had a capacity increase in 1986 to 1188cc, as the FJ1200. There were more minor changes in 1988, but perhaps the most significant was the ABS option launched in 1991. Like the XJ900, the FJ is still in production.
Maybe this success with the bigger fours gave Yamaha more confidence with the similar ones. The Diversion 600 of 1991 certainly suggested this. There was nothing very radical about it, but it was a very good seller where the old XJ600 was not. Its 600cc four was a much simplified version of the Genesis concept, still with a slant forward block, but with air-cooling and two valves per cylinder. Despite, or perhaps because of the modest specification, the Diversion proved to be an excellent all rounder, which is what many people still want from a motorbike. Available in naked and half-faired forms, it was good valve and a deserved success. The 600cc class moved on so fast in the nineties that the Diversion was very much the budget option, the 95bhp Fazer 600 from 1998 being more contemporary.
Diversion 600
The V-Max on the other hand, could never be described as a sensible all rounder. Launched in 1985, it was an unashamed performance muscle machine, with sheer acceleration and speed, its single purpose goal. It looked like nothing else, with the surprisingly compact liquid-cooled 1198cc V4 of the Gold Wing style XVZ12, but with larger carburettors and valves, not to mention higher compression, stronger valve-springs and toughened bottom end. It is hardly surprising that the V-Max became something of a cult motorbike.
By the early 1980's, Yamaha had built successful four-stroke singles and tourers, but had yet to really take the sportbike market by storm. That came in 1985 with the FZ750. There was much new about the FZ, specifically its liquid-cooled 749cc four, with five valves per cylinder. Over a long development period, Yamaha engineers had experimented with six and even seven valve heads before settling on five as the best compromise between power and reliability. The cylinder-block was slanted forward at 45 degrees to lower the centre of gravity and allow good, straight inlet and exhaust ports, not to mention space for the four down-draught carburettors. It all added up to a very efficient and powerful engine that gave Yamaha class leadership for a while. It was folowed up in 1987 with the FZR1000 Genesis, whose main innovation was an alloy box section frame known as Deltabox. The latter was a big step forward, giving a lower seat height and far better handling than the steel framed FZ750. The engine was simply an enlarged 750, though with great attention paid to weight and space saving. Power was 135bhp, with a 165mph top speed.
New Sport, New Standards
Yamaha had not forgotten its smaller motorbikes, and still fovoured he two-stroke. The TZR125 of 1988 used a reed-valved two-stroke single together with the latest Deltabox frame. It came with or without a fairing, and was a great success. More intriguing was the TDR250, an attempt at mirroring the big TDM850 with a trail motorbike style but with road tyres and road performance. The twin-cylinder two-stroke gave an amazing 107mph maximum speed, and the TDR certainly provided an alternative to race replicas.
R1 (1999)
In the 1990's two motorbikes stand out. I've mentioned how the FZR series seemed t lose its way a little as the Thundercat and Thunderace. The motorbikes that changed all that were the R1 in 1998, and the R6 of 1999. The R1 is a milestone motorbike, setting new standards in the one-litre supersports class. It is lighter, smaller and more powerful than any of its rivals, and great play is made of the 'three figures' 150bhp, 177kg and 1,395mm shortest wheelbase. The R1 was the first of a new family of supersports motorbikes, including a 750cc R7 for superbike racing and a 599cc R6. With the R6, Yamaha had done it again. More power than any other 600, and it is marginally lighter than them all as well, its top speed being over 170mph. For a mere 600 it gives astonishing performance, and underlines the fact that Yamaha intended to hold tight to its sportsbike market leadership.
In : Japanese Motorcycles
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