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/127649
Tetsuya Harada's Yamaha TZM250 Tetsuya Harada's World Championshipwinning TZM250 features Yamaha's 90degree V-twin 250cc powerplantln a twinspar aluminum frame. After riding the TZM250, tester Alan cathcart was more prone to praise Harada than Yamaha for winning the title. 24 EPROM chips. Unlike on the YZR, where both carbs face forward for improved ram air induction, only the front/lower cylinder's carb does so on the TZM, with the rear carb facing backwards. However, the carefully developed system of fairing ducts and carbon-fiber trunking feeding cool air to the pair of sealed, pressurized airboxes one for each carb, of course - which appeared at Hockenheim for the first time, was a key factor in keeping engine development on the boil, says Yoda-san, as well as delivering a top speed of 167.4 mph when properly jetted; nearly five mph more than in '92. . "The bikes we took to Jerez for the IRTA tests in February had the same specifications as the year before," he said, "but we had a constant supply of new parts all through the season, which allowed us to improve engine performance a lot. But the airbox system was the biggest help in keeping pace with our rivals, and allowing Harada-san to ride the bike to its maximum potential." So, if you strip awa y the implied criticism about the Yamaha's engine perfor- mance compared to its rivals, and focus on its strong points, this leaves you with a bike that has outstanding mid-range performance, with excellent torque between 9000-12,500 rpm. Right - so how to take advantage of this, bearing in mind that more and more circuits nowadays are slower rather than faster, making it a smart choice to tune the bike like this if you can't have it both ways? The TZM was a 101 more of a top-end bike in 1991 than it is now, or was last year when Schmid started getting on the pace with it. The solution is to tailor the chassis to suit the rider's every wish, allowing him to maximize cornering speeds and get the jump on the more powerful opposition that way. Ah, but what happens if you have riders with greatly contrasting styles and setups? Well, let's just say that Harada has lived with the TZM for some time, and that the development of the bike has inevitably been centered around his tastes and needs. For Chili, adapting to the Yamaha after riding the Aprilia must have been quite d ifficult. It's a bike on which he must have found it very hard to alter his tastes for a "scaled-down 500" in terms of chassis geometry and rid ing position - making his decision to become a team player and help Harada all he could in pursuit of the world title all the more pragmatic, as well as praiseworthy. The wa y Tetsuya has the TZM set up is quite unusual by modem GP standards, reflecting his spirit of individuality that was, perhaps, a key factor in enabling him to clinch the world title with this machine. He did it his way. "My set-up is based on the idea that if the tum-in is improved, rear traction out of turns will also be improved because the time needed to keep the machine leaned over becomes shorter," Harada explains. "So I have the bike set up in order to be able to take any line on . the race track, and after that to get the necessary traction - I always want to be able to choose any riding line I want, especially in a battle with other riders in a race. Being able to vary my lines is the most important thing."