Now into its second year, our reigning class champ has all the tools it needs to compete, including a slipper clutch, radial-mount brake master cylinder and front calipers, and the most powerful four-cylinder motor of the group.
Kawasaki ZX-6R Lovable Cheater
In last year’s Supersport Shootout, no bike could match the sheer thrust of the 636cc ZX-6R, and that has been a significant factor since the “cheater” motor first debuted in 2003. But what took the Kawi to the top of the rankings last year was enhanced handling composure and a dramatic upturn in style. It was also the first middleweight to include features such as an exhaust powervalve and a sweet back-torque-limiting clutch.
But with all the new players in this class, suddenly the feature-laden ZX looks a bit more Spartan. The bike’s just as good as ever, but the bold new players make the Kawi seem almost like yesterday’s news.
To start off with, let’s begin with the only change made for ’06: a slightly shorter windscreen. We noted in last year’s shootout the screen’s trailing edge would obscure the view of the (still unintelligible) tachometer, and this is the easy remedy. It’s nice to know somebody’s listening.
Otherwise, this is the same brute that thrilled us so much last year. The middleweight class has become more compact and racy, and this is both a blessing and a curse. The dominant impression when climbing aboard is the ZX’s size. It feels long, and the tip of its nose is further away than the bulldoggish snouts of the other Multis.
That large physical impression might mislead some to think bigger equals heavier, but the Ninja ties the freshly baked R6 for the second-lightest of the group. And the relatively expansive cockpit turns out to be a friendly place to do business.
“Commuters and long-distance riders will love the plush seat and slightly conservative ergos,” says Chamberlain. “Taller riders like me benefit from sitting down in the bike a little more than the other contenders, enabling you to tuck in without too much discomfort.”
The only time comfort (relatively speaking) becomes an issue is during highway drones. Apparently a 6% bigger engine displacement produces at least that much extra vibration that creeps into the handlebars and to your hands. It’s otherwise quite civil for a sportbike of such credibility.
BC has always loved the ZX’s “cheater” motor, as its 636cc provides more thrust throughout the powerband than the other Fours. “Putting out more horsepower and a much broader curve, you won’t be left unsatisfied,” he says.
The ZX is one of the best bikes in this test for riding around town. It not only holds a consistent power advantage over the other Fours, it also has shorter gearing in the first two cogs than everything but the R6.
“There is good feel at the clutch lever,” BC notes, “and it is easy to modulate while taking off from stop signs or staging lights.”
“Its extra displacement gives it the edge on the true 600cc machines by offering just a bit more grunt off the bottom and in the midrange,” says Kenny.
That surplus of power results in top-gear roll-ons that kill the 600s, even matching the torquey Daytona from 80 mph, and it also comes in handy during more aggressive use, as the ZX can often carry a gear higher through a corner than the Fours.
“The power comes on hard way down low and continues to pull hard higher in the rpm than most street riders will be willing to go,” says BC, one of our resident hooligans you see pulling wheelies in our pics and videos. “The low-end hit makes it my bike of choice for our wheelie shots. It will easily power-wheelie in first gear, and just a slight slip of the clutch will bring it up in second. If low and midrange power isn’t enough for you, don’t worry, it still pulls as hard as anything in the class at the top of the rev range.” Indeed, the ZX has a 3300-rpm spread where it makes more than 100 hp, the largest top-end range of the group.
The 2005 revisions to the ZX’s chassis geometry dramatically calmed the formerly twitchy Ninja, as it has mid-pack trail and wheelbase figures along with the laziest rake of them all. However, a heavy and/or aggressive rider can encounter a bit of headshake under acceleration if the suspension isn’t set optimally. Because the chassis geometry is nothing radical, we theorize the ZX’s slightly rearward weigh bias and raging power causes an excess amount of longitudinal weight transfer that breaks the front tire’s grasp with the road.
Most of our testers didn’t suffer this effect and were generally pleased with the Ninja’s handling qualities. Its wide bars provide the necessary leverage to overcome the lazy rake in steering transitions, but not all of us felt secure at the bike’s limits.
Like all the bikes in this test, the ZX has plenty of cornering clearance for any sane street rider.
“Side-to-side transitions require a little more work than some of the quicker-steering bikes,” notes BC. “Once in the corner, the Kawi is very stable and the rear end provides lots of feel. Unfortunately, front-end feel is less pronounced and you kind of have to just trust it.”
No such complaints about the Kwacker’s suspension, which received nearly universal praise. And although the ZX’s front brake rotors are the smallest in diameter (but thicker to help dissipate heat), they were also highly rated thanks to their radial mounting and one of the few radial master cylinders in the group.
Last year, we described the 6R’s appearance as sexy. Now, among this group of edgy combatants, its rounded styling cues suddenly look a bit dated. Perhaps the paint’s matte finish on our test bike helped make the ZX, shall we say, lose its luster. Despite its ambitious title (Candy Flat Raw Plasma Blue), the color wasn’t a hit among our testers. Three other colors are available, including green, black (our favorite), or a special edition in silver with burgundy tribal flames and matching wheels.
“Although only two years into its cycle, the ZX is starting to look and feel a little large in comparison to the new anorexic models that are now walking the streets,” BC critiques.
So, a rider dismounts the roomy Kawi raving about its motor, and walks out of the dealer wild about the lowest price of this group.
“The ZX-6R is a great choice for someone wanting a good machine to ride around on the streets, with strong power, decent cornering and great brakes,” Haldane notes. “On top of all this, it’s a pretty comfortable bike.”
“The ZX is still a formidable streetbike in the middleweight class,” adds Kenny.