Effectively melding the design philosophy of its MotoGP racing division with its street-going, production-based supersport machine, Kawasaki has retired the 636 offering to concentrate their middleweight efforts solely on the 600. The result is an all-new Ninja ZX-6R.
The ZX-6R represents a significant retooling of Kawasaki’s popular and successful supersport weapon, driven as much by knife-edge technology as a theoretical approach to tackling a race circuit. MotoGP, which are downsizing from 990cc powerplants to 800s has inspired a shift in engineering pursuits—improved handling and cornering characteristics are favored over ultimate horsepower.
RIDING STYLE: Helmet: AGV TiTech. Leathers: MotoGP 1-Piece. Kangaroo Hide Compression Suit. Gloves: MotoGP RPM. Boots: Sidi Vertigo Corsa. Photograph by Tom Riles. (Click image to enlarge)
The new Ninja is smaller, more nimble, extremely responsive race bikes, capable of faster corner entry and higher mid-turn speed. Early tests in MotoGP have proven the concept, with the new generation machines already cutting lap times equivalent to, and in some cases faster, than the 990cc machines. If there is any doubt that Kawasaki was concentrating on compacting the ZX-6R, its selection of a former 125cc Grand Prix racer as the ZX-6R’s chief development rider erases any questions.
The key to the Ninjas’s success is mass centralization—getting more of the motorcycle’s weight closer to its center, rendering a neutral handling, less sensitive motorcycle. The improved feedback results in increased confidence on turn-in—especially at speed—with a planted demeanor mid-corner that lends itself to getting on to the throttle sooner for quicker exits.
Photograph by Tom Riles. (Click image to enlarge)
Instead of coaxing more ponies out of the 599cc liquid-cooled, in-line-4, engineers worked at broadening the powerband, spreading the 116 horses (same specification as last year) over a wider, more usable spectrum. The ZX-6R enjoys ample torque, strong mid-range, and a screaming top end that translates to a more forgiving temperament on the track regarding shift points and throttle application. This allows the rider to concentrate on lines and brake points rather than worrying about trying to maintain engine speed.
A healthy allowance for over-rev has been built-in, reducing the potential of redlining the machine. With peak performance arriving at 12,500 rpm and an over-rev ceiling of 16,000, there’s plenty of room to stay on the throttle a little longer, when necessary, and avoid a gear-change, if the situation warrants. This is an extension of the racing philos-ophy, giving the rider more latitude to ride the way that best suits his style and the track layout.
Married to the wide powerband, the close-ratio 6-speed cassette transmission makes it easier to use the performance of the Ninja. The slipper clutch alleviates the chances of skipping the rear wheel on hard downshifts, synchronizing the engine revs with rear wheel speed for smooth corner entry.The new chassis represents an engineering goal of matching rider input with response by actually slowing down the machine’s tendencies. The engineers conceived a “split-second pause” when flicking the bike into a corner to smooth out the bike’s motion and keep the rider and machine together. It appears to have worked. The Ninja has tremendously predictable turn-in, responding to the slightest of rider commands, accented with a solid, planted feel. However, when cresting a rise, hard on the gas, the front wheel gets light, inducing some serious headshake. The ZX-6R would certainly benefit from a steering stabilization system.
Photograph by Kevin Wing. (Click image to enlarge)
The bike’s feathery agility conceals its claimed dry weight of 402 lbs, a few marks on the scale heavier than some of its classmates. The 41mm inverted front forks mount the springs at the bottom, submerging them in oil for consistent damping characteristics. Rear suspension utilizes a gas-charged shock in Kawasaki’s shock linkage with a special top-out spring. A radial-pump front brake master cylinder provides superlative feel to the radial-mounted petal discs up front, allowing for plenty of confidence when trail-braking deep into corners.
The cockpit is all business. Although suitable for daily rides, the bike has an aggressive seating position, derivative of a race machine. Extremely slim, the ZX-6R allows the rider to crawl around with minimal effort. The fuel tank works exceptionally well as an anchor to hook the thigh on in
corners, or grab with the legs under braking. Thankfully, Kawasaki abandoned its peculiar perimeter tacho-meter in favor of a big, bold-faced clock that’s easy to find when you have nothing more than a split-second to steal a peek at the dash.
Photograph by Kevin Wing.
The 2007 ZX-6R is a reminder that the days of middleweight sport bikes built primarily for everyday street functionality with adaptability for the racetrack are long gone. Kawasaki has unabashedly borrowed heavily from its MotoGP effort, then affixed a license plate bracket and lights to the result. “Let the competition compromise performance for rider-friendliness,” Kawasaki proclaims in its press kit, leaving us no room to kid ourselves or anyone else—the machine is a strafing weapon for racetracks.