TWO-STROKE TERRORS

TWO-STROKE TERRORS

Mat Oxley YEARS AGO A NEW WORLD CHAMPIONSHIP GAVE bith to a crazy kind of tyre-shredding, piston-meting motorcycle. The Formula 750 series was designed to give

the latest 750 four-stroke road bikes somewhere to play, safe from the marauding two-stroke Grand Prix machines that had come to dominate all forms of bike racing.

F750 would allow Triumph to show off its booming threecylinder Trident and it would give Honda a chance to race its new CB750. Just to be sure, GP two-strokes would be excluded by a requirement for a minimum production run of 200 engines.

But a four-stroke never won an F750 race. By the time the series stated in 1973, a new kind of 750 two-stroke racer had taken the world by storm. Kawasaki's H2R, using the engine from the fiery H2 road bike, and Suzuki's TR750, powered by the GT750 'kettle' roadster gave the four-strokes no chance at all. Where the Trident and CB750 were topped out at 150mph, the two-strokes would come streaking past 25mph faster.

They demanded a high price for theft 100bhp performance. "They were absolute animals," says Paul Smart (above) who saw his life flash before him many a time on TR7505 and H2s. "The handling was appalling and the reliability was abysmal. They used to shed bits and overheat because you had to use standard cylinder and crankcase castings, so everything was on the ragged edge."

"The huge Achilles heel riding those bloody things was that the tyres couldn't stand the huge increase in speed," adds Smart. "When we got to the American speedbowls the bikes were doing 175mph and the tyres would do two laps and fly to pieces. Suddenly you'd get this vibration and 'bang" the tyre exploded. It drove you round the bend; you dreaded your next race." The tyre engineers had to do something, and they did. "Dunlop worked day and night," says Smart. "Then one day they said they'd sorted the problem. They took me into a darkened room

and there it was: a tyre with no f—king tread on it. They said you've got to believe us, this will work."

Accidents still happened. Smat's brother-in-law Barry Sheene was the most famous victim of that unholy trinity: an F750 bike, inadequate rubber and an American speedbowl. During testing for the 1975 Daytona 200 Sheene's rear tyre exploded, hurling him down the banking at 170mph. Sheene, who had won the first F750 prize in 1973, lost half the skin off his back and broke a femur, an arm, a few ribs and several vertebrae.

And then the bikes got even faster. While Suzuki and Kawasaki had steadily developed their three-cylinder road engines into world-dominating machines, Yamaha had a better idea. They read the rulebook and decided to build 200 F750 race bikes. The four-cylinderTZ750 (née 700) may have been designed specifically for the racetrack, but early models suggested otherwise.

"Oh boy, it was scary," says Steve Baker who became America's first road racing world champion when he won the 1977 F750 title. "It would flex the frame so bad that at I-don'tknow-how-many miles an our it would get into a violent tanksapper, and you couldn't stop it."

The TZ750 went on to become arguably the greatest race bike of all time, dominating F750 for years and ultimately contributing to the championship's demise at the end of 1979. The 140bhp weapon was so good that the series essentially became a onemake championship.

When 2011 MotoGP World Champion Casey Stoner recently announced hB retirement he was asked t anything mgt tempt him back. "Yeah, 750 two-strokes" he replied.

Stoner who likes to fight a bike wasn't even born when F750 was alive, which proves the reputation of these awesome motorcycles. We will not see their like again, and I'm not sure t that's a good or a bad thing.