Kawasaki had the engine parts for its new ZX-6R Ninja spread out on a table in the pit suite at Barber Motorsports Park in Birmingham, Alabama, for all to see. As we looked at the pieces that make up the extraordinary powertrain in this fast new bike, it was hard to reconcile the tiny, exquisitely wrought components with the sheer ferocity of the machines flashing past outside on the track, their engines screaming at over 15,000 rpm.
Kawasaki spokesmen say this 2007 Ninja has the first completely new 600 engine in ten years--now smaller and lighter in almost every way--and yet their product presentations emphasized the redeveloped chassis even more than they did the high-revving, 16,500-rpm jewel that was laid out like the internals of some intricate timepiece. Perhaps it shows how confident Kawasaki is about its engine-building prowess. Knowing it could produce a competitive engine, the company concentrated on developing a chassis unlike anything Kawasaki had done before. And to make sure it was done right, the company put engineers from its motorsport program on the job, with former 125cc grand prix competitor Tomomi Manako assigned as test rider. By balancing rigidity and compliance in the chassis, equipping the machine with high-quality, finely adjustable suspension components and the latest Bridgestone tires, and then tuning the combination exhaustively, Kawasaki has produced a remarkable track tool.
But does that mean this thing is rolling purgatory on the road? Probably not, judging from the relatively comfortable riding position we all enjoyed on the track. The seat pad is sized and angled carefully to spread the load evenly, and the handlebar-to-footpeg relationship felt just fine during the half-hour sessions we rode.
Another aspect that will undoubtedly make the ZX-6R a handy road bike is a comparatively broad spread of power. Despite the dizzying 16,500 rpm redline, the bike pulls handily in the midrange, with real urge available quite low on the dial. It also seemed not to fall into a bog-hole at very low revs, and I once had the bike pull me slowly but smoothly back into the pits with little more than 2000 rpm under the needle.
The Kawasaki engineers refer to the high rev-ceiling as "over-rev capacity", which is handy when there isn't time for a shift, or when you're cornering so hard there just isn't room under the shift lever for your foot. Since peak power arrives at 12,500 rpm, and the engine begins to fade a little near redline, over-rev is exactly what it feels like.
Still, the usable range is pretty impressive, particularly since it can be exploited by the carefully staged six-speed cassette transmission, and the equally effective slipper clutch. With a light action and positive selection, the gearbox encourages frequent use, while the clutch's easily detected take-up point and linear engagement process were as reassuring as its ability to absorb early downshifts without unsticking the rear tire.
There's really not much wrong with the powertrain in this bike, and the assembled riders were unanimously enthusiastic about it. And if the engine and gearbox are good, then the chassis is sensational. Able to track in a straight line with reassuring stability, the ZX-6R nonetheless turns in at the merest suggestion of pressure at the bars, and tips easily to whatever angle your skill level allows with very little resistance.
You might expect a machine developed for the track to be stiff and uncompromising, but the Kawasaki is responsive and easy to ride. And even when a big handful of throttle out of Barber's turn five hairpin picks the front wheel up, the bars just paw at the air gently in your hands before touching back down. What makes that lack of drama memorable is that this bike isn't even fitted with a steering damper. Of course, Kawasaki works rider Roger Hayden's new ZX-6R racebike is equipped with a nice expensive Ohlins damper, but then he's using considerable persuasion to make the bike respond at speeds that most people shouldn't even think about, let alone try.
Mere mortals like us will appreciate the stability of this bike, the ease and precision with which its controls can be operated, and the reassurance this lends the rider. That such a track-ready mount can feel so approachable is a measure of the machine's remarkable range. The chassis seems able to manage conflicting forces without having to be over-controlled. At least, that's how it was on the relatively smooth surface of George Barber's delightful little racetrack.
There's an aspect of the new machine that doesn't require a public road or a longer loan. That's the apparent improvement in manufacturing and assembly values evident on the new ZX-6R. The castings, moldings and fittings were pretty flawless on the bikes we rode, suggesting that Kawasaki has brought a new level of quality to its little Ninja. All of which ought to stoke the already fierce competition in the 600 sport bike arena to a white-hot pitch, and provide consumers with pretty rich pickings.