Green, it seems, is the freshest buzz-word to sweep the planet. “Green this, green that,” exhort the Capital Hill privileged that purportedly represent us overtaxed payers. While politicians produce enough hot CO2 to feed a forest and burn through newly printed notes as if they grew on trees, my idea of eco-friendly transportation is the pair of irrefutably green machines we have here.
The latest in a long line of green sportbikes, Kawasaki’s lime-colored Ninja ZX-6R has been thoroughly reworked for 2009. Now even Big Red has boarded the G train, offering its CBR600RR in a timely metallic-green-on-black paint scheme. Either of these middleweight sportbikes represents a righteous purchase at a time when excess may be viewed as a self-indulgent character flaw. Fact is, both of these bikes are powerhouse performers well capable of running with the liter-class elite on many roads and racetracks.
Honda has locked down the honor of Best Middleweight Streetbike the past two years in Cycle World’s Ten Best Bikes balloting. Aside from offering a sport-ABS option(our testbike was the non-ABS version), Honda has elected to play out its hand in 2009 with no significant changes to the 600RR. Kawasaki has risen to the challenge with a host of 6R updates aimed at improved midrange delivery and sharper handling. Headlining the list of ZX-6R chassis changes is the use of a Showa Big Piston Fork, providing improved damping control, primarily during the stroke’s change of direction.
Before we pitted the two bikes head-to-head at the track and on the street, each was rolled onto the Cycle Worldscales and dyno. At 398 pounds without fuel, the Kawi has shed an impressive 16 pounds, closing up on the 386-pound class-featherweight CBR. Comparing dyno charts reveals the fruits of Kawasaki’s labor. A very broad torque spread builds steadily off idle and hits its stride at 8000 rpm, maintaining 40-plus foot-pounds beyond 14,000 rpm. The Honda holds a slight edge in torque production from 8000 to 12,000 rpm, but it rolls over on top with a 10-hp disparity to the 6R’s impressive 110.2 peak horsepower at 14,000 rpm. Both offer generous over-rev with power tailing off out to their respective 15,000-rpm rev-limiters.
Pulling cleanly away from a stop is equally easy aboard either bike, with very little throttle application or revs above idle required to do so. Neither bike suffers from any hint of hesitation at basement revs in its lower gears, making each a pleasure to ride in town. The same holds true for the slick shifting action when working through their six-speed gearboxes. A tangible difference is revealed at freeway cruise speeds: Both run in the same 6500–7000-rpm range at an indicated 70–80 mph, but the ZX-6R clearly stands out, with only a hint of vibration seeping through its bars. Not that the mild, high-pitched tingle felt in the CBR grips is a deal-breaker, but the difference is noticeable.
Larger riders will find the ZX-6R more spacious than the CBR, its riding position a bit more spread out with a slightly longer reach to the bars. The tinted ZX windscreen is also taller, offering a little more wind protection, but shorter riders may find that the turbulent airflow over the top of the screen rocks their helmets. Both have very roomy saddles allowing plenty of fore/aft movement and making it easy to fold into a full-tuck position.
Both saddles are narrow where they meet the tank, resulting in less leg-reach to the ground, with the ZX’s slimmer midsection and .4-inch-lower seat height favoring shorter riders in that regard.
While ride comfort over freeway slabs is no big priority for either of these supersports, both are adept once the suspension clickers have been dialed back. Even standard settings provided a tolerable degree of stiff compliance on the highway, and steering response and chassis composure proved excellent for backroad blitzing.
Back-to-back runs to the top of nearby Glendora Mountain Road provided as much of a distinction between the bikes’ power delivery characteristics as had the freeway transit for comparative vibration levels. A spirited street pace on this twisty stretch of two-lane made frequent use of second and third gear, with an occasional visit to fourth throughout the uphill climb. The CBR’s 599cc inline-Four pulled with an electric rheostat-like connection between twistgrip and rear tire exiting every corner—even uphill third-gear bends that saw revs drop to 7000 rpm. Despite sharing identical bore-and-stroke dimensions with the Honda, the ZX-6R, by contrast, displayed softness below 8000 rpm that had previously gone unnoticed. A discernable rush of acceleration comes on at 8000 rpm, lending credence to the newly restyled tachometer face that places visual emphasis on rpm increments at 8000 revs and above.
Both felt wonderfully surefooted when hustled corner-to-corner, never giving the slightest hint of instability. The CBR’s weight advantage and 1-inch-shorter wheelbase make for slightly lighter steering, most evident in quick side-to-side transitions between linked corners.
A steady tailwind influenced our dragstrip results with hero times and trap speeds through the quarter-mile. The CBR’s upper-midrange strength gave it a holeshot advantage that the ZX’s top-end surge was unable to overcome. Our test site is located 2500 feet above sea level, so it stands to reason that at lower elevation the ZX would require much less clutch slip to get off the line with authority.
Our final phase of testing took us to the bumpy and technically busy Streets of Willow Springs road course. It proved an ideal venue for the Ninja’s BPF front end to strut its stuff, the most perceptible difference being a reduced rate of dive when aggressively applying the brakes compared to the CBR’s conventional inverted cartridge fork. The ZX also exhibited less fore-aft chassis pitch than did the CBR, characteristic of a firm setup, yet it matched the CBR’s level of bump absorption. Both bikes are equipped with a steering damper, an electronically auto-adjust unit on the CBR and a manually adjustable Öhlins damper on the ZX. While both machines exhibited headshake while crossing the same couple of patches of rough surface, the Kawasaki maintained superior composure and instilled greater rider confidence. The Ninja’s slight edge in handling competence and top-end power proved an unbeatable combination, posting a best lap time of 1:23.10 to the CBR’s quickest of 1:23.55.
Quality of fit and finish is superb on both, but we give the nod to the Kawi for its more inspiring styling. It also offers a more feature-rich instrument cluster with its gear-selection indicator, shift light and lap-timing mode.
The middleweight performance environment has never looked better. While I’m no tree-hugger, picking a winner between this pair of green machines feels like felling a beautiful redwood. While each is deserving, Kawasaki has grown stronger while Honda has stood still. Price is a factor, as well; at $9799 the Ninja undercuts the CBR by $700.
