Track-Ready, Supersport Motorcycle
Having surrendered the AMA 600cc Supersport title in 2008, Kawasaki is clearly anxious to get it back. The previous Ninja iteration was a good machine, but the all-new Kawasaki Ninja ZX-6R is in a different league altogether, as we found out at Autopolis–Kawasaki’s spectacular racetrack just outside Kumamoto, Japan.
Even at rest, the ZX-6R’s ground-up redesign is obvious. The styling is now much closer in looks to its ZX-10R big brother; the squint-eyed projector-beam headlights, furrowed brow, high tail, and tight side-exit exhaust give this Ninja an equally mean, aggressive demeanor.
Despite the compact nature of a 600, the ergonomics of the new ZX-6R impressed me with its intuitive fit; it is comfortable, even with my gangly six-foot frame aboard. The cockpit’s large, white-faced rev-counter has an LCD digital display to the right, showing speed and gear position. It is beautifully easy to read, and the green band highlight on the tachometer denotes the optimum power range–that tops out at a shrieking 16,500 rpm.
However, the new styling only hints at the dramatic improvements Kawasaki has made to the ZX-6R. The top-end power–124 hp without ram-air effect, boosted to an astonishing 130 hp with it–is clearly awesome. More noticeably, the greatly improved mid-range torque makes the new Ninja easier to ride and, presumably, a more practical street bike, too.
It was through the final two Autopolis corners leading to the straight where the improved mid-range power truly became apparent to me. Although the motor was willing to hold second gear, I quickly discovered I could carry third without sacrificing drive off the corner. This meant I did not run out of revs in the middle of the following quick kink onto the straight, and then have to grapple awkwardly for an upshift with my weight hard on the left footpeg.
This midrange boost comes from several highly technical, detailed motor upgrades. They include dual-height velocity stacks (effectively creating double inlets for each cylinder) and an improved transition between the throttle bodies smoothing the intake airflow. The durable nitride hard-coat-finished cam and tappet surfaces allow more aggressive cam timing, while re-profiled pistons, molybdenum-coated skirts, and lower-tension piston rings dramatically reduce frictional losses. The exhaust also helps the engine exhale more efficiently, and still stay street-legal and sounding good.
Interestingly, it is difficult to decide which part of Kawasaki’s new screamer is the most welcome improvement. While the aforementioned new motor is particularly good,Kawasaki has–again through many detail enhancements–created an even tighter-handling motorcycle that is a pure joy to ride no matter what type of corner you throw yourself into.
This enhanced handling is partly due to some forward shrinking from Kawasaki that reduced the ZX-6R’s overall weight by a stunning 22 lbs. In a class where weight savings are typically measured in ounces, to shed 22 big ones from an already high-tech machine is an astounding achievement–who knew the previous model was so portly? That weight loss alone is highly signficant but, in addition, the remaining weight has been carefully mass-centralized. Involving more than simply relocating the exhaust from under the seat, the engine is also tilted forward and the head stock raised to move the center of gravity over a half-inch higher.
With its tighter caster angle (down a click to 24 degrees) and a lowered seat (almost a quarter-inch), the bike turns in if you merely think about it. Yet, front tire feedback was so good I never lost confidence in the front end. The ZX-6Ris absolutely scalpel precise; I could hit my mark each time because the chassis stayed neutral, but turned without hesitation. Even at speed and tucked in, the Ninja went exactly where I wanted. Mid-corner stability is excellent; the only quirk I found was cresting over the quick-flick right and uphill left of turns 14/15 where the Ninja would headshake in the transition as the front wheel lifted off; seemingly the newly added Öhlins steering damper is a little weak, even on its stiffest setting.
Exiting the lower hairpin and coming back hard on the throttle in second gear, the ZX-6R was cured from running just a little wide by stiffening the rear Showa shock a tad. One turn of preload, one click of rebound damping and one of high-speed compression was all it took for me to be able to exit the bottom hairpin flat out in second while leaned over hard on my right knee. The revised swingarm and pivot gave good rear wheel feedback; there was no discernable squirming or weaving at all and the exemplary Bridgestone BT-003 track tires never gave even a hint of sliding.
The straight at Autopolis is long, and tapped out in fifth gear at the end translated to just over 150 mph. Turn 1 is a little off-camber and slightly downhill, so hard braking is needed for the relatively slow corner. Kawasaki’s brakes have always had amazing feel, and happily they remain unchanged. The 300mm petal rotors, radial pump and calipers work precisely and powerfully, without being grabby.
The cassette-style race-ready gearbox links to the back wheel via slipper clutch, and Kawasaki has the spring/ramp tension set perfectly. There is definitely rear wheel braking, but the back-torque is limited enough that the rear tire never hops or chatters. Coming down from a buck-fifty definitely keeps you awake, and being able to slow down quickly, progressively and smoothly really helped me stay focused on my turn-in point.
Additional credit for that stability has to go to the newly developed Showa Big Piston Fork–one of those brilliantly simple ideas that makes one wonder why it wasn’t thought of before. Compared to a similar cartridge-type fork, the BPF’s main piston is almost twice the size, and the oil inside acts on almost four times the surface area. This allows a reduction in pressure, but ensures the actual damping force remains the same. The slider moves much more consistently and gives greater control over the initial fork stroke.
The result is that on initial brake application the chassis stays calm and stable and doesn’t pitch forward dramatically. Technically, it is not anti-dive, but it does reduce the initial drop at the front and again, for me, it kept the ZX-6R stable and smooth when I needed it most.
Winning is in the details, and the strain of ultra-competitive DNA that is wound through Kawasaki has driven it to take the already excellent Ninja ZX-6R to a whole new level. By methodically redesigning even the tiniest detail, Kawasaki has created an incredibly impressive SuperSport motorcycle that is the perfect track day tool, right out-of-the-box. I suspect the 2009 racing year will back me up on that. FEBRUARY / MARCH 2009 ULTIMATE MOTORCYCLING
See: Our ZX-6R Review in our Video Section
Helmet: Arai Corsair V
Leathers: Kushitani K0050XX
Gloves: Dainese Piston
Boots: Sidi Vertigo Corsa