Dateline: Birmingham, Alabama, December 7, 2006
"You won't believe this," Motorcyclist contributor Jim West said as we walked the golf course the day before Kawasaki unveiled its all-new ZX-6R at Barber Motorsports Park, "but tomorrow's high is only gonna be 40 degrees."
I didn't believe him. Yeah, the Southern states had been hit with a cold spell, and we'd needed turtlenecks and windbreakers on the links this day. But in the 30s? In the South? That seemed unlikely.
It wasn't. When we walked out of the Ross Bridge Resort the next morning, the water fountain out front was frozen, and the temperature was a frigid 18 degrees-not a record (minus 27 back in '66), but bone-chilling nonetheless.
It was no better at the track, especially with the windchill at about 7 degrees. As I thought about suiting up for my first session, I taped shut the vents on my gloves and wished I'd brought an electric vest and a snowmobile suit instead of vented leathers. My first stint on the 6R ended after just four laps, by which point my fingers were frozen and burning with pain-it was all I could do to feel the controls as I rode in. It took me 20 minutes to thaw the bloodless digits, which meant my first session was about as useful as snow skis in Panama. Session two was no better.
Toward noon, fortunately, temperatures climbed into the high 20s-warm enough to allow more than a few laps on the bike at one time. Also fortunate was Kawasaki's choice of tires for the day: Bridgestone BT002 radials, DOT race tires which stuck to the frozen asphalt way better than they had a right to. I was worried about grip early on. Race tires usually don't warm as quickly as street skins, but the 002s stuck surprisingly well in the a.m. and got stickier as temperatures inched toward the low 40s later in the day.
And the bike? First off, the all-new ZX-6R is entirely new, with nothing from the '05-'06 model making the trip to '07. Kawasaki hasn't built a truly all-new 600 in a decade, previous generations of the 6R having been repeatedly tweaked to keep pace. Of course, with Suzuki, Yamaha and Triumph having unleashed lighter and faster new-generation middleweights in '06, and Honda launching an all-new CBR600RR for '07, Kawasaki obviously felt the time was ripe for a fresh design.
And what a design it is! Start with the engine: a liquid-cooled, 16-valve, 599cc four that's shorter, lighter, narrower and significantly more compact than the 636cc mill it replaces. Kawasaki swung for the fences with this one. The engine's not only smaller and lighter than the 636, but also reportedly lower in friction internally and higher in both torque and peak power, all while offering more midrange grunt and a seamless, stepless power delivery.
That's a tall order in an era of 110-plus-horsepower, 15,000-rpm, durable middleweight engines, especially when you're dealing with 37 fewer cubes. But during my half-dozen racetrack stints on the new 6R, even while stressing about grip and potential frostbite, the new engine made me a believer with its linear power delivery, electric-like smoothness, generous midrange punch, useful slipper clutch and what felt to me like class-leading top-end oomph. Kawasaki claims peak power of 118 bhp at 12,500 rpm for U.S. and Canadian versions and 125 bhp at 14,000 for Euro- and Australian-spec bikes, the gap due to the different exhaust-valve tuning necessary to get the bike through stringent U.S. emissions testing.
I'd ridden Honda's new CBR600RR at Barber 10 days earlier (see road test this issue), and if I had to guess (using my finely calibrated heinie-dyno), I'd say it and the Kawi are about equal in terms of peak power. The CBR might make a bit more midrange, although gearing-and the frigid weather at the Ninja launch-could have affected my perceptions. Still, the 6R offered up tons of rip along with above average over-rev, which allowed me to stretch a particular gear a bit longer rather than upshifting and then having to downshift for the upcoming corner. What- ever the dyno finally says, these two new-gen engines are hugely impressive-so powerful, flexible and smooth it'll take a full-blown street and track comparison to suss out what will likely be minute differences between them.
Kawasaki's engineers also spent considerable time on the chassis, involving-as Honda did-its MotoGP team in the development effort. Going into the project two Going into the project two years ago, the team's primary goal for the bike was to combine the power characteristics of a fully tuned 600cc Super- sport machine with the handling and cornering performance of a lightweight, small-displacement GP racer. To do this, engineers designed controlled flex into the twin-spar aluminum frame to handle mid-corner surface imperfections without upsetting the bike. That's longhand for what Honda called Tuned Flex a few years ago.
"The 6R's chassis works in harmony with the rider's reflexes," ZX-6R Project Leader Tasuhisa Okabe told me at dinner in the Barber museum the night before our test ride. In my experience, that sort of statement often ends up in the blather bin, but I found myself agreeing with Okabe-san as I got up to speed on the 6R the following day. Highly flickable from full-lean left to full-lean right (a bit more so than the CBR), and offering a ton of front-end and overall traction feedback (again, a smidge more than the Honda), the 6R was immediately comfortable at speed on the roller coaster-esque Barber circuit. In fact, with just a few turns of preload up front and out back, and some minor fiddling with the compression and rebound clickers on the fork and shock, the bike was easily able to handle my 225 pounds, which says a lot about the goodness of the spring and damping settings the development team settled on. Best of all, the suspension had that hard-to-find combination of plushness and wheel control, which bodes well for the bike's street manners.
The 6R's brakes-radially mounted Nissin calipers grabbing 300mm petal discs-proved as competent as anything I've tried, including the new CBR's. In fact, the only fly in the Green One's ointment was a bit of headshake exiting corners and while cresting uphills with the throttle pinned. A steering damper (like the Honda's excellent electronic unit) is needed, but Kawasaki obviously feels it's something owners can fit themselves.
In fact, the chassis was even more impressive than the ultra-smooth engine, which says a lot about Kawasaki's latest middleweight. Twenty years ago, a Honda TV spot claimed, "Even the Ninja hides from the Hurricane." That may have been true then, but I'm not betting against Team Green in 2007. This bike is that good.
2007 Kawasaki Zx-6r
|MSRP ||$8999 |
|Type || l-c inline-four |
|Valves ||DOHC, 16v |
|Displacement ||599cc |
|Transmission ||6-speed |
|Weight || 368 lb. (167kg) |
|Fuel capacity ||4.5 gal. (17L) |
|Wheelbase ||55.3 in. (1405mm) |
|Seat height ||32.3 in. (820mm) |