Cycle News - Archive Issues - 1990's

INTERVIEW Yamaha's general manager of engineering Toshimitsu Iio By Dennis Noyes t has been what the Spanish call "a shouted secret" for several months. The Japanese manufacturers and top IRTA leaders are openly calling for a switch from two-stroke to "four-stroke power in the SOOcc class of Grand Prix racing. Toshimitsu lio, general manager of the First Engineering Division of Yamaha Motor Company, leaped at the opportunity to address this matter during an in terview prior to the Spanish GP. He was quick to support, at least in theory, Mick Doohan's call (made in a Speedvision TV interview at Jerez) for a quick abandonment of two-so-oke SODs and a change to lOOOce four-cylinder four-stroke powerplants (see sidebar). Mr. lio also made it clear that he is firmly committed to restoring Yamaha to its former place of glory in Grand Prix racing's premier class and that, in spite of strong success so far this season in AMA Supercross, the Paris-Dakar Rally and World Superbike, SOOcc GP racing continues to be the top priority and "the top challenge" for Yamaha. Yamaha opened the year with Scott Russell's win in the Daytona 200. That was followed with a stunning performance by Noriyuki Haga in the opening rounds of the World Superbike Championship, plus a podium fir)ish by Haga in his 50Dcc Grand Prix debut at Suzuka. Add to this the Dakar win by Stephane Peter hansel on the XTZ850TRZ and the AMA Supercross title won by Jeremy McGrath, and you see that if Yamaha and Mr. lio wished to do so, they could have taken a tri-umphant tone and down played their lack of recent GP success. The one fact that disturbs the Yamaha racing department is that last year, for the first time in 34 years, Yamaha didn't win a single GP in any of the three cia ses. But Yamaha has a long commitment to Grand Prix racing and that was .part of the message that Mr. lio wished tal communicate when we spoke to him at Jerez. The other part of the message, however, was that GP racing has gotten .out of touch with the products that Yamaha and the other GP manufacturers now sell and what the market demands. We opened our interview with a general leading question. His response indicated that Yamaha, the first manufacturer to win a 500cc world title with a two-stroke (when Giacomo Agostini on the Yamal1a piston-ported, across-theframe four took the 500cc title from Phil Read on the MV Agusta four-stroke four), is leaning toward a change. The rules in 50Dcc racing have not really changed very much at all for about 40 years. If we compare SOOcc racing with Formula One, NASCAR, Indycar, or almost any other form of motorsports, we see that there is a big difference between the rules now and 40 years ago. Do you think it is time to think of changing the formula for the SOOcc class? Generally, as long as the rules are the same for all competitors, then they are fair, but when the social trends, sales trends and consumer atmosphere have already changed then it is time for rules to change, ·too. Today people are concerned about the environment and almost all production machines are four-strokes. When we saw the new laws in California making it impossible to legally register a two-stroke off-road bike for 1998, we decided we would develop the 400cc four-stroke for motocross and supereross. We have learned that California's regulations set the trend not just for the United States but for all developed countries. But isn't it possible with fuel injection, for example, to make the two-stroke engine environmentally friendly? That depends upon the level of contamination that the rules of the future will tolerate. It is possible to meet today's rules with the two-stroke, but for the future it will always be easier and more economical to reach the desired levels with a four-stroke engine. It looks like the only area where there is still development of the two-stroke engine is in racing, and maybe just in road racing if motocross goes to fourstrokes. This is a problem. It is true that the twostroke engine has certain advantages. It is compact and delivers very good performance in relation to its capacity. It has a racing character, but we believe that even in GP racing the engine should be related to 'the product that Yamaha makes. It is also true that in racing, changes are sometimes necessary just to renew interest and enthusiasm. Even though the reasons for developing the four-stroke come from environmental and market concerns, it is also important to see that in motocross we have had no big manges for many years and then, when a new macl1ine and a new sound - the four-stroke sound - came to the tracks, it increased the motivation of the engineers who are making the innovations and it increased. the enthusiasm of the fans. In road racing we ha ve had no real rule changes for many years. Mick Doohan said recently in a TV interview with an American satellite channel that he believes that the current two-stroke technology is no longer related to real motorcycles that people ride on the street. He thinks we need to stop racing two-strokes just as fast as we can. He believes we should be racing lOOOcc four-strokes - but that if we try and develop smaller, 600cc fourstrokes with GP regulations, the bikes will need to rev too mum to be reliable. That in tum will mean they will be too expensive and iliey will be slower than real 5OOs.

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