Column vol.15
View our column profiling Yamaha's 50 years of involvement in racing. Vol.15Defeated by its own invincibility, the
Gene Romero won the 1975 Daytona 200 on the TZ750R
The Formula 750 (F750) was contested by up to 750cc "production" machines of no fewer than 200 were been built and marketed. F750 racing included the Europe-centered FIM Cup and the All Japan Road Race Championship, started in 1973.
In the US AMA championships, however, big-bike races like the Daytona 200 had been popular from before that time. From the late 1960s, large-displacement Japanese machines by Honda, Suzuki and Kawasaki joined Harley-Davidson, Norton and Triumph makes in these races, resulting in a more dynamic big bike scene.
Yamaha, which had no big-displacement models apart from the 650cc XS-1 twin, entered the Daytona 200 from 1967 with its 350cc TR-2 prototype model (YZ608) production racer. After privateer Don Emdel won an initial Daytona victory on the TR-3 in 1972, Jarno Saarinen rode a TZ350 prototype (YZ634) the following year to give Yamaha a second win.
It was clear, however, that Yamaha could not win future races with these models, so development was started on a 700cc production racer from 1971 ― the TZ750 (YZ648). In 1974, the resulting TZ750 was entered for the first time in the Daytona 200 in a factory specification (0W19) and was ridden by Giacomo Agostini and Kenny Roberts to a spectacular 1-2 finish debut win.
The following year, Yamaha upped displacement to 750cc to introduce a new production model (TZ750R) and the factory spec YZR750 (0W29). In addition to winner Gene Romero (TZ750R), Steve Baker, Johnny Cecotto, Agostini and other Yamaha riders swept the first 16 places on this new machine.
The YZR750 (0W31) ridden by Steve Baker, the first winner of the F750 World Championship in 1977. Baker won five victories, including the Daytona 200. From 1977, a new frame, Monocross suspension and other 0W31-based specs were also applied to the production TZ750 (launched in Japan in 1978)
From 1974, many TZ750s were entered in the F750 class of the All Japan Road Race Championship and the FIM Cup. In addition to Yamaha's domestic teams, racing was dominated by riders signed with Yamaha dealerships and importers around the world, and these Yamaha machines gradually overwhelmed all the other makers.
Then, in 1977, when a F750 world championship was launched, Yamaha released a new TZ750 model inheriting the Monocross suspension and other specifications of the YZR750 (0W31). Like the TZ250/350 that dominated the World GP250 and GP350 at that time, the new TZ750 monopolized the starting grid in all F750 category races.
Ironically, however, this ended up hastening the demise of Yamaha's TZ750 and YZR750 models.
One reason was that frame and tire performance could not keep up with engine performance after max. power output was increased to nearly 160PS. As a result, machine durability suffered.
Another factor was that unlike the former F750 series, where riders had contested the title on the basis of effective points scored in their best five races, the World GP750 title was now contested on the basis of total points system for all the races in the series in an attempt to increase the number of riders in each race. That meant that only factory team riders or privateers with the financial resources to contest all races in the series had a chance of winning the title. In reality, champions Steve Baker (1977), Johnny Cecotto (1978) and Patrick Pons (1979) were all Yamaha contracted riders.
As a result, the F750 World Championship folded after just three years, and the TZ750 could no longer remain in production.
Despite this, the TZ750s and YZR750s that were still on the market were raced in the United States' AMA Formula 1 class, where F750 machines with carburetor restrictions could compete against 4-stroke machines of up to 1,025cc and 500cc GP machines. In the Daytona 200 in particular, the TZ750 and YZR750 were undefeated from the year of their debut until Graeme Crosby's win (0W31) in 1982, giving Yamaha streak of nine consecutive victories.*
Meanwhile, in Europe the TZ750 engine, which was also used for GP machines with sidecars, supported winning machines for a long time.
This peerless machine with its liquid-cooled, 2-stroke, piston reed valve 748cc in-line-four engine became legendary for its unmatched speed on the track before disappearing with the F750 and the passing of an age.
*If the time of Kenny Roberts is included, then Yamaha machines won 13 consecutive victories from the 1972 TR-3 (Don Emdel) to the 1984 YZR700 (0W69).
