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/127824
RIDING IMPRESSION peak power on par with its competitors. The principal step in power comes at around 8000 rpm, after which the engine produces a steady if somewhat measured climb in revs to the 13,000 rpm redline. This newfound flexibility and increase in overall horsepower is the result of several changes to the 599cc four. Forged pistons that are said to be both Lighter and stronger replace the cast pieces used previously, and a revised ignition system that now uses a throttle position sensor is said to improve engine response at small throttle openings as well as to provide greater power at higher revs. The exhaust system also underwent several changes in an effort to augment the midrange, including a joint pipe between the two of the 4-2-1 exhaust system and the addition of a punched cone' inside the silencer. This addition of horsepower brought about some other changes in an effort to cope with the attendant heat penalty such an increase brings: namely a larger, Liquid-cooled oil cooler and new friction-plate and spring material in the clutch. The lever pull is light on the cable-actuated clutch but its use is hampered By Mark Hoyer t's got to be tough building a sportbike for the 600cc class. It is a class in which racing success is highly regarded, so there's a lot on the Line, saleswise, if the machine isTI't successful on the track. Does that mean that a manufacturer should strive to make the Lightest, fastest, most uncompromising racer its designers and engineers can concoct? Or should a company bow to the fact that, in reality, the overwhelming percentage of buyers will use the machine for a more quotidian application, such as commuting, during which time ground clearance will not be tested, sticky tires will not be scuffed to th.eir edges and shifts will not take place near redline. It is sometimes clear where the line of compromise is drawn. Witness the a11new GSXR600 from Suzuki. It is the quintessential race track refugee squarely aimed at carrying its rider to weekly champagne showers. That some of its purchasers might not use it that way is of no matter. It rips, and doesn't stop to ask you if you're comfortable. Other times it is not so clear where the tough decisions and inevitable compromises were made. Witness the 1997 YZF600R, Yamaha's heavily revamped premier middleweight supersport contender. It is a motorcycle that blurs the line of compromise and goes a long way toward delivering fo its rider the best of all worlds. The most important area of change on the YZF is to its twin-cam, fourvalve-per-cyLinder Genesis slant-block powerplant. It is here that the Yamaha bucks the current trend in the sportbike world a bit by offering an engine with a stroke several millimeters longer than (Above) While the most obvious change to Yamaha's 1997 YZF600R Is Its sleek new styling, changes under the skin make the real difference In the machine's personality. (Right) Though heavier than Its competitors, the VZF's extra weight Is only noticeable on the quickest of transitions. (Below) The new front brakes with single-piece calipers offer strong Initial bite and good feel. The front fender Is a two-piece design and an Integral part of the more aerodynamic fairing. any of the other bikes in its class. A longer stroke for a given displacement is typically associated with torque-oriented power output, and a solid, torquey feel is what the YZF delivers. The YZF is perfectly content motoring around in the bottom half of its rev range and can be short shifted without feeling like you're pulJing an anchor when you roll the gas on. However, this torque doesn't entirely come at the expense of topend power. WhiJe the YZF doesn't deliver the high-rpm whack of some of the other bikes in its class, it nonetheless performs admirably as the revs rise and, in fact, delivers by a narrow engagement range and some judder on hard launches. While the Little YZF's bore and stroke ratio sets it apart from its competitors, a new induction system brings it right in Line. Though Yamaha doesn't call it ram air, it looks a lot' like it to us. And to quote Yamaha's own press material on the subject, the YZF gets "a new aircleaner assembly structure for greater power at high speed." In any case, gone is the conventional system that sees the air inlet under th.e fuel tank somewhere, breathing hot, engine-heated air, and in its place is a fresh-air intake under the