The gorgeous shores of Daytona Beach in Florida, USA, boast sand comfortable for barefoot strolls, but the beaches of this Atlantic coastal city have also played host to motorcycle races in the past, with Norton and Harley-Davidson machines racing around oval tracks carved into that sand. And some 7 kilometers from the beachfront lies the legendary Daytona International Speedway.
On March 11, 1973, it was a hot and humid day not very different from midsummer in Japan. Yamaha was competing in the Daytona 200, which unofficially kicked off the world’s motorsports season. It was the preamble for the Yamaha factory team’s long-awaited return to the Road Racing World Championship Grand Prix after a five-year hiatus. Finnish rider and 1972 250cc World Champion Jarno Saarinen rode a prototype TZ350 production racer to win the race, beating 750cc machines on his way to the checkers. It was a great show of force in preparation for the 500cc GP campaign.
British racers Rodney Gould and Phil Read rode production TD-2s to win successive 250cc Grand Prix titles in 1970 and 1971, respectively. At that time, the TD-2 dominated the top of the class rankings, with 10 of the top 20 riders of 1969 on TDs, 15 in 1970, and 18 in 1971. While the TD was originally developed for amateur racing, it had become the undisputed number one mount to have in the world’s top racing series.
While development of these production racers continued, Yamaha was also simultaneously developing its first factory YZR500 for Grand Prix’s 500cc class and a 700cc machine meant for the Daytona 200. To ensure development efficiency and technical reliability with the machines, two 2-cylinder engines from the 250cc TD-2 and two from the 350cc TR-2 were lined up and coupled to form in-line 4-cylinder power units, one at 500cc and one at 700cc. The knowledge Yamaha had gained through building production racers was put to full use in creating these two new 4-cylinder mills.
Then in 1972, the FIM created the new Formula 750 (F750) racing class, and in 1973 it became a new standalone series run on a separate calendar from the Grand Prix World Championship. Race fans were excited about the future in store with this new F750 class.
In 1973, Yamaha had gotten off to a strong start in the opening stages of the World Championship, but a major on-track incident at Round 4 in Italy changed everything. During the 250cc race, Saarinen was involved in a massive multi-bike crash on the first lap and sadly lost his life. In mourning, Yamaha canceled its factory effort for the rest of the year.
Around the same time, there was an upheaval in the global economy. One U.S. dollar had been worth 308 yen in the fixed exchange rate system established by the Smithsonian Agreement, but in February 1973, Japan changed to a floating exchange rate regime, a development the country’s export industry found difficult to swallow. In October that same year, Japan was hit by the first oil crisis, triggered by the embargo instituted by Middle Eastern oil producers. The ensuing spike in oil prices plunged the global economy into a dark period with no foreseeable end.
Agostini and Kanaya comprised the factory team the following year in 1975. Once again piloting the YZR500, they battled against Phil Read on the MV Agusta and the Suzukis of Länsivuori and British star Barry Sheene, with Agostini coming out on top to win the title. For Agostini, it was his first championship triumph since his 350cc title for MV Agusta in 1973 and Yamaha’s first 500cc premier-class Rider title.
Kanaya played a pivotal role in raising the competitiveness of the YZR500. He secured his first 500cc race victory in Austria, but as Agostini found his stride with back-to-back wins in West Germany and Italy, Kanaya withdrew from the championship and returned to Japan to focus on helping further sharpen the YZR500.
Many in the media felt that if he had instead kept competing, Kanaya would have been in with a chance of lifting the title, but Yamaha had him come back to Japan and work closely with the engineers and mechanics to support Agostini’s championship challenge in a show of teamwork embodying Yamaha’s racing spirit.
The Monocross single-shock suspension and Yamaha Power Valve System (YPVS) were major contributors to the performance of Yamaha’s factory racebikes in the 1970s. The former debuted on the 1974 YZR500, with the shock positioned below the fuel tank to allow for longer wheel travel and more mass centralization, resulting in more stable handling.
The latter was designed to improve 2-stroke engine performance. In 1977 at the Finland GP, Venezuela’s Johnny Cecotto rode the first YZR500 (0W35) with YPVS. The technology was refined and fitted to the YZR500 (0W35K) in 1978, on which “King” Kenny Roberts clinched his first of three successive 500cc titles (1978–1980), demonstrating the benefits of YPVS on the racetrack.
These two technologies were not conceived from the outset to improve the competitiveness of Yamaha’s racing machines. In fact, their origins lay in different disciplines altogether. The Monocross suspension came from the motocross world, while YPVS was born of research to address exhaust emissions and improve eco-friendliness. The Monocross suspension was the brainchild of Belgian engineering professor Lucien Tilkins. Yamaha purchased the patent for the design and built a monoshock to use in its motocross machines. The design was instrumental in Yamaha winning the 1973 250cc Motocross World Championship title with Hakan Andersson.
Of course, Yamaha did not reuse the shock from its factory motocross bike as-is. “While there are no structural differences from the motocross version, we did change the setup,” said engineer Makoto Sugiyama. “We needed a greater degree of fine tuning, so we added an adapter gear to adjust shock length, included damping force adjustability and the like. The riders praised the handling improvements thanks to the better cushioning performance and mass centralization the shock brought.”
YPVS was originally derived from research Yamaha was conducting into various means of meeting emissions regulations. The 1970 amendments to the Clean Air Act in the United States made regulations on exhaust emissions stricter, prompting many manufacturers to begin exhaust gas purification research. The exhaust gas of a 2-stroke engine contains about one-tenth the nitrous oxide of a 4-stroke engine, but since 2-stroke engines do not have intake and exhaust valves, the blow-by effect results in the gas containing much more hydrocarbons instead.
It was during efforts to solve this that YPVS was born. The system places a variable valve near the exhaust port that moves according to engine revs, providing the same power at high rpm, but also delivering strong pull at low and mid-range rpm. “YPVS was incredibly effective in terms of its benefits for road racing,” acknowledged one engineer. “We saw a two-second advantage while testing at the Yamaha test course.” Both of these technologies live on today and stand as shining examples of innovative Yamaha technologies that continue to progress even now.
In light of the uncertainties with the global economy, Yamaha ceased all factory efforts outside Japan in 1976, but maintained a presence in GP paddock by supplying top riders with factory-spec machines through European importers, thereby keeping the excitement on the GP scene high. Yamaha also called on its relationships with the technicians and others involved in the series. A team manager at the time shared his perspective: “Unlike the ‘60s when our work was mostly done by Yamaha employees, back then in ‘75 and ‘76 we had more and more people involved with the teams like part vendors and sponsors. That broadened our perspective and is the reason we were able to continue racing for so long. We learned that if we had only stuck to keeping things entirely in-house, it wouldn’t have lasted.”
In the 500cc premier class in 1976, Suzuki took eight wins from ten races, limiting Yamaha and MV Agusta to one win each. With Suzuki’s RG500 turning them into a force on the grid, Yamaha revamped its rider lineup for 1977. American racer Steve Baker joined Cecotto in the 500cc class on a new YZR500, but Sheene rode the square 4-cylinder RG500 to a second consecutive title. While Baker was unable to take a race win, he was a regular on the podium and finished as the runner-up. Cecotto sealed two wins but suffered injuries, leaving him 4th in the points.
But Yamaha’s situation changed in 1978 with Kenny Roberts joining the team and being armed with the YPVS-equipped YZR500 (0W35K). Roberts had a dirt track racing background from his years in the AMA and a then-unique riding style in which he hung off the bike through corners. He also brought his own motorhome to each round, and in these ways, he slowly went on to change the norms of GP racing and its paddock culture.
Roberts’ exploits from 1978 onward are already well documented by the media, so there is no need to go into detail here, but his relationship with Yamaha can be summarized with his own words. After injuring himself in a crash during pre-season tests in 1979, Roberts was forced to spend a month recovering in the hospital. “That was when one of the Yamaha racing bosses came to visit me in the hospital and had a contract for me to sign. He told me that everyone was waiting for me to come back. It made me realize that Yamaha really cares about its people.”
Roberts returned to action at Round 2 in Austria that April, riding the second YZR500 to feature YPVS, the 0W45. He took the win and went on to victory another four times to claim a second consecutive premier-class title. He repeated the feat again in 1980, making it three titles in as many years.
The Formula 750 (F750) class officially became a world championship in 1977, and expectations were high that it could surpass 500cc as the pinnacle racing class. Yamaha entered with its YZR750 while supplying privateers with the TZ750 to energize the new series.
Yamaha released a new TZ750 featuring a Monocross suspension and other technical spec changes, and in the same way TZ models were sweeping the 250cc and 350cc GP classes at the time, the number of TZ750s on the F750 grid was overwhelming and there was no way for competitors to gain a foothold in the class. Yamaha thus won three consecutive titles in the F750 series with Baker in 1977 on a YZR750, Cecotto in 1978 also on a YZR750 and French rider Patrick Pons on a TZ750 in 1979.
However, the engine could put out up to 160 horsepower and the bike reached 300 km/h in testing, making it far too much performance for frames and tires of the time to handle. Plus, each rider’s points were calculated based on their best performances across the season, so teams with the leeway to race in more rounds had an advantage. This was why the series only lasted three years before it was scrapped.
Even so, Yamaha’s large-displacement 2-strokes continued to shine on the east coast of the United States. Before 4-stroke “superbikes” took over, Yamaha won an incredible 13 consecutive Daytona 200s, beginning with Don Emde in 1972 and ending with Roberts’ win in 1984. This utter domination made it nearly impossible to talk about the Daytona without mentioning Yamaha’s involvement.
Then in 1979, Honda returned to Grand Prix for the first time in 11 years, and with Suzuki also upping its own efforts, Grand Prix racing in the 1980s became a battle among the Japanese manufacturers for wins and titles.