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/128111
Andrew Pitt/lain Macpherson s Kawasaki ZX-6R World Supersport Racer This year's Kawasaki uses a 5mm longer rear shock, throwing more weight to the front wheel for Improved grip. The shock Is a WP unit. testing, when compromised settings meant it was too rich low down and lugged out of Most's far hairpin or chicane complex, but with better midrange and good top-end speed down the long main straight. Going in the other direction next morning meant the same bike was fluffy at the top end next time I rode it - but then Gopp & Co. tore into the carbs for my final session on Andrew's bike, and fixed it. But it takes time: maybe the fuel-injected Supersport contenders from Honda and Suzuki have an edge, here - not to mention the Ducatis. But once set up and flying right, the Kawasaki engine is a real gem, coming on strong as low as 8000 rpm with a controllable but very noticeable extra surge of power from 10,000 revs upward. Short-shifting at 12,000 rpm around a long left hander leading away from the hairpin, where you're cranked hard over and the street-pattern gearbox becomes a hassle, still delivered good drive thanks to the engine's torquey nature, which must make it a flexible friend for the cut 'n' thrust of Supersport racing, where you may have to back off the throttle fast when someone cuts in front of you and spoils your drive, but then on the Kawasaki can get back on it again without having to shift gears and buzz the engine back into the zone where serious power is delivered. On the ZX-6R, that zone is a mile wide compared to some of its rivals, making this a fast but forgiving bike two attributes that are usually mutually exclusive, but which Gopp's conservative tuning and Kawasaki's good engineering have indeed delivered here. "I port the cylinder head, but make sure it's not too muchl" says Gopp, who pays special attention to modifying ·the combustion chamber, widening the valve seats correctly for better precision in seating and an improved flow, and 28 JULY 4, 2001 • cue I • getting the critical valve to piston clearance just right with the revised-shaped pistons on the new Jl engine, which have a different squish area than before. Uttle things mean a lot. Same thing with the chassis, where revised steering geometry has produced a bike which is even more stable on fast, sweeping bends, yet turns in better in tight ones, partly also thanks to the 5mm longer rear shock which steepens the effective fork angle, as well as throwing more weight on to the front wheel, for better grip. Again, chassiswise too the Kawasaki feels very solid and robust, without being heavy-steering or unweildy: within the 1415mm wheelbase there's lots of space for a sixfoot rider, who feels much more a part of the bike than being perched atop the skinnier-seeming R6, or squeezed for space like on the short-seeming Suzuki and arguably even the Honda. And there's better rider protection than on any of these - though Pitt thinks this may be too much of a good thing. "I can slipstream the better R6s and the Ten Kate Hondas, but I can't pull out and pass them," he says. "The bodywork seems to push a lot of air, plus the ram-air intake doesn't seem as good as the Yamahas'. Our top speed is okay [175.4 mph at Hockenheim last year puts the ZX-6R right in the ballgame], but we don't have the reserves of power at the top end that the others have - it's more a torquey kind of bike." Macpherson agrees: "The Kawasaki pulls okay on acceleration out of turns, but once you get into fifth or sixth gear, you lose out," he says. "But the handling is good, though the WP suspension takes longer to set up than the Ohlins, because it's got both high- and low-speed adjustment which the Ohlins didn't - it's definitely more sophisticated and will let you do more. That's why 2000 had to be a learning year - but now we have all the data, and know where we're going." Okay, the ZX-6R isn't as nimble as the Yamaha in slow turns, but it arguably feels more planted in faster ones, and is definitely more stable on the brakes than before - like braking hard for Most's second-gear final bend, which on the old IX-6R would have been a recipe for the bike to start squirming around under the excessive weight transfer from the hefty stopping power of those six-piston Tokico calipers. Here, on the new bike, there are two major improvements, One, the pitch (i.e. distance between the legs) of the 46mm upside-down forks has increased, fork offset is reduced to newws give more trail, and the forks shortened, with the c1ip-ons now mounted under the upper triple clamp, no longer above it, in tum shoving more of the rider's weight forward onto the wheel. Together with WP fork internals and the new model's modified chassis with more meat around the steering head, all this makes for a stiffer frontend package that makes the Kawasaki considerably more stable than the '99 bike under heavy braking or high suspension loads - so more compliant under hard cornering. Two, the Tokico calipers now have differentially-sized pistons, a racetrack-derived trick which enhances initial response and gives a more progressive feel to the lever, without sacrificing the balls-out stopping power the Kawasaki already possessed, even with its smaller stock 300mm discs which are retained, and before Gopp has saved .88 of a pound in unsprung weight by machining down the inside circumference of the discs, to remove that part of the metal not actually swept by the pads. After Gopp had fumed up the suspension for my extra pounds compared to the 138-pound Pitt and 143pound Macpherson pocket rocket physiques, and dialed in more rebound damping in the forks to stop them pumping over the Most bumps induced by the 100,OOO-spectator Truck GPs which are the track's main income-earners, the Macpherson Kawasaki felt really taut and compliant, the all-new and much stiffer swingarm combining with the good grip from the Dunlop tires to put the power down well out of Most's many turns, even over the unforgiving ripples exiting the last turn, where the admittedly more powerful IX- 7RR Superbike I was also riding had tried to pump itself into knots. But then when I swapped onto Pitt's ZX-6R, I found it much looser than lain's bike, with harder fork damping that made it leap around over bumps, causing the front wheel to flap around in a passable imitation of a full-scale tank-slapper coming on to the pit straight. It was also more unstable under heavy braking, caused by a combination of the stiffer forks and Andrew's thick seat pad, which accentuate front-end weight bias for extra grip, but only at the cost of getting the back end light and waving around when you stop hard. Made the fifth gear left/right flick at the end of the pit straight interesting, to say the least - or the chicane before the hairpin. If I preferred the chassis setup of the Macpherson bike, I can't say I liked the brakes as much on his as Andrew's, because lain runs both the clutch and brake levers very close to the handlebars, and after five laps or so the lever gets aII soggy and comes back to the bar. His bike was much Look, Ma, no fuel Injection. Four 3l5mm Mikunis feed the bike its fuel. more stable under heavy braking than either his old one, or the new Pitt bike - but while it stopped well, you didn't always feel you had enough lever to do so. Strange - the brakes on the old IX-6R were fantastic, only the flexyflier chassis compromising the stopping power. But on the new one, there's arguably even more initial bite, only not such a good feel to the brakes, almost as if it didn't have braided steel hoses (which it does). Master cylinder? But Macpherson's softer suspension settings - still finn enough to be compliant, though - together with that great, forgiving engine, make this a very effective package. Don't be surprised to see the pair of green screamies in contention for victory as the World Supersport season unfolds and maybe even, at last, the title. But still - why aren't there more Kawasakis out there? It's a mystery. CIII The front fort< on the Eckl bikes are 4flmm Kawasaki units with WP internals. Toklco calipers are used on both the front and rear discs.