Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/127665
ยท-' Then so mething curious ha ppened . A couple of poor race result s left the team members scratchin g their heads and going back to the factory, w here they found some "variations" in geometry be tw ee n the successful prototype an d the prod uctio n bikes. This is a hiccup in the slow-andste ady approach which won them the title last year, thou gh they are now able to pick up w ith a basically good bike, and start again. The engine is outwardly similar to last year's, the twin-crank 7o-degree Vfour having only minor internal modifica tions for th e new fuel. The usual secrecy prevails, but fuel ad ditives as much as metallurgy and engineering are reckoned to have played the major part in preserving power outputs. The chassis is also similar to what was used previous ly, changes ha ving concentra ted on refining steering and suspension geometry an d weight distrib u tion. The goal has always been to m ake the bike more user-frie ndly and better balanced, but in Australia the old p ro blem o f skittishness had returned . Suzuki's po licy is to go forw ard step ' by step. Th us it was rela tively eas y for th em to go one stage back when the new bike proved faulty. Only time will tell if th ey will be able to go forwa rd again from there...an d indeed if they will need to. YAM AHA Ac co rding to all rep orts, the 1994 works Yamaha is an all-new up-to-theminute d esign con tinuing on the factary's frame development from last year, and with the updated engine using fuel injection. Unfortu na tely, th ere is no way to verify any of th is, because the bike was rejected early in pre-season tests by both Luca Cadalora and Daryl Beattie, and Team Marlboro Roberts switched forth with back to an updated vers ion of the bike they raced in the latter part of last year. In this the y followed the lead set by Wayne Rainey last year, although the American only made the same mo ve halfway through the year. Th e Roc cha ssis ha s benefited from detail im p ro ve men ts over the years, m ainl y concerned wi th refining geometry, so that th e bike is close to perfect with all adjustments in the center of the a va il a b le range. These adj ustm ents incl ude en gine and swinga rm po sition, as well as the usual possible variables to steering head angle, etc.. Less is kn own about the changes to the engine, except that the crankcases were s trengthened las t yea r by switching from magnesium to aluminium after the switch to vibration-inducing close firing order had resulted in several blow-ups in 1992. Thus the works Yamaha seen at the GP tracks owes its major design features not jus t to last year's bike, bu t in fact to the 1991 machine. That bik e wa s th e basis for the Roc chassis, as used by the current machine; while the YZR500 motor is fundamentally the same, excep t for the crucia l incorporation of Big Bang close firing order. The Yamaha riders may be close to Vintage Bike racing, but it is a tribute to the fun damental sound ness of the origi nal, well-ro u nded bike that it is still fully competitive today. Or perhaps it is just further proof, along with the lack of improvement in lap times, that developm en t of t he V-four 590 has already passed its peak. We will know more about that when th e Aprilia V-twin hits the tra cks later this year. a