As the factory Kawasaki engineers responsible for the new '09 ZX-6R were introduced, we noticed a familiar face in the crowd. Yasuhisa Okabe was the project leader for the team that redesigned the current ZX-10R, so when he was presented as the project leader for the new 600cc Ninja, it was easy to surmise that the same racetrack-oriented design philosophy of the bigger Kawasaki would be infused into the newest model as well. "Kawasaki's recent consumer research found that riders interested in purchasing a 600 weren't concerned with comfort or other street-going compromises. Outright performance was the single largest factor in the purchase decision," revealed Karl Edmondson, Kawasaki Motor Corp USA product manager.
Of course, the styling similarities between the new generation ZX-6R and the current ZX-10R would probably be your first clue. There's no doubt that the previous 6R definitely needed a power boost, but extracting additional ponies from a little 600cc engine is a far tougher proposition than a literbike powerplant. Would the new ZX-6R turn out to be a high-strung thoroughbred requiring a lot of skill from the rider to extract that performance?
The new ZX-6R's instrument...
The new ZX-6R's instrument panel is much more efficient in design and easier to read. The weird bar graph gear indicator has been replaced with a fairly conspicuous digital readout in the upper left corner of the LCD panel, and the rpm numbers on the analog tach are larger and much easier to discern at a glance. A shift indicator light to the upper left of the tach is actually easy to notice, even in daylight.
More Than Just Skin Deep
We previewed most of the changes to the new 6R in our December issue ("New Bikes 2009"), but for a recap you can check out the accompanying tech sidebar on page 32. There were plenty of new detail changes, however, that came to light during the bike's world press introduction held at Kawasaki's superb Autopolis International Racing Circuit in southern Japan.
Kawasaki was particularly proud of how much weight was shaved with the new 6R. And if the claims turn out to be true when we finally put a production model on our own scales, then the engineers have every reason to be pleased; 22 pounds is an enormous amount of weight to lose from a 600, where components are usually already pared down to the bare minimum. For instance, using chromoly steel in the camshaft construction saved approximately 400 grams, while magnesium engine covers dropped approximately 680 grams (with removable noise reduction pads inside comprising another 340 grams that can be deducted for racing) and narrower transmission gears cut 170 grams. Changes to the EFI construction dropped 200 grams, and the new titanium underengine exhaust system comes in 960 grams less than the previous unit. Alterations to the cooling system design dropped another 350 grams, with the new frame cutting an additional 7.7 pounds. Even the bodywork contributed more than four pounds to the weight loss count. All told, the new ZX-6R is claimed to weigh in at 421 pounds wet (full fuel tank, ready to ride), a 23-pound reduction from the somewhat porky 444 pounds we recorded in our '08 600 comparison test ("Balancing Act", July '08).
Optimized cam surface nitriding and more durable tappets allow more aggressive cam profiles for better all-around performance. A revised exhaust collector layout (still a 4-into-2-into-1 setup, but with subtle changes to the header balancer tubes and collector design) contributes to improved low-end and midrange power without sacrificing flow for top-end power.
Ergonomics have been revised, with the seat 5mm lower (as well as narrower at the seat/tank junction) and the clip-on bars moved closer to the rider and angled back a bit more. The seat is also shorter in length, working with the reshaped fuel tank to allow more contact areas with the rider for improved feedback.
Front brakes are still the...
Front brakes are still the same radial-mount/four-pad Nissin calipers biting on 300mm petal rotors, but the rotors have grown in thickness from 5.5mm to 6mm to better withstand track use.
Other small but notable changes include an adjustable Ohlins race steering damper to keep the steeper steering geometry from causing any headshake tendencies, and an increase in front brake disc thickness from 5.5mm to 6mm (diameter remains the same at 300mm) to enable improved heat dissipation during aggressive riding at the track.
The '09 ZX-6R will be available in Metallic Diablo Black, Candy Surf Blue or the usual Kawasaki racing Lime Green version for $9799. An extra $200 buys the special Monster Energy edition that is all black except for a lime green seat and lime green pinstripe along the circumference of the wheels.
What Hath Thou Wrought?
Although the new ZX-6R doesn't seem any smaller than its predecessor when you initially sit on it-the flared top of the fuel tank and the angular fairing give a false impression of size-that changes quickly when you first set your feet on the pegs and notice the narrower midsection, shorter reach to the bars, and shorter seat. There's more of a compact feel to the new 6R, even though the overall dimensions are basically the same.
That feeling is accentuated the moment you flick the Kawasaki into a turn. Whether through the more centralized mass (the engine is actually raised on the countershaft axis 4.6 degrees to reduce the polar moment of inertia) or due to the sharper steering numbers (24 degrees rake/103mm trail from 25.1 degrees/110mm), the new 6R is definitely easier to bend into a turn, requiring less effort in all aspects of steering. This was especially noticeable in Autopolis' many switchback sections that require pulling the bike from full lean on one side to the other; while the previous generation 6R was by no means truckish in this regard, the '09 Ninja has a more lithe feel that translates to quicker transitions with less effort. Granted, the ZX-6Rs we rode at Autopolis were all equipped with Bridgestone BT-003 DOT racing rubber that surely contributed to the more agile steering, but the difference was too great to be attributed to just the tires.
Thankfully that sharper and quicker steering hasn't come at the expense of stability. Even though Autopolis' pavement is a literal billiard table compared to 99 percent of American racing circuits, there are still plenty of fast sections that test a bike's ability to maintain composure while accelerating hard over bumps at moderate lean angles. The Kawasaki never felt like it was coming unglued at any time, even with initial suspension settings that were a bit too soft in the rear. We never felt the need to tighten up the Ohlins steering damper (which is actually a good thing, considering that even when cranked up to maximum, the OEM-spec Ohlins' overall damping rate is fairly light).
We're not sure if the new Showa BPF inverted fork played a role in that stability, but there was no doubt of the fork's aptitude at handling any situation we were able to put it through at Autopolis-ditto for the rear shock. We must admit, however, that we didn't notice the same difference in performance that we've experienced when switching to aftermarket fork cartridge kits on other bikes, although it should be pointed out that the Japanese circuit has very little of the pavement imperfections that plague most of the American racetracks we test at. With fewer and less harsh corner entry and midcorner bumps to really expose any high-speed damping deficiencies, it was difficult to discern any real improvement with the BPF, so we'll have to reserve judgment until we get a production model onto our less-than-perfect tarmac.
With its near-3000 feet altitude, the thin air of the mountain highlands where the Autopolis circuit is nestled tends to rob engine power, but even accounting for that factor, it was immediately apparent that the new ZX-6R powerplant is a major improvement over the old unit (even with the jumper wire mod to access the Euro engine map). The huge midrange hole that afflicted the previous model has been filled in nicely and then some, meaning that many tighter sections of the Autopolis circuit could be taken in third gear to maintain momentum, something that the old 6R could only dream of. That stronger midrange transcends into an even stouter top-end that not only towers over the old strangled U.S. version by a claimed (and astounding) eight horsepower, but the new U.S. version now only trails the Euro-spec '09 Ninja by less than two horsepower at peak.
This diagram illustrates the...
This diagram illustrates the concept employed by the Kawasaki's "multi-boring thread insert" plain bearings. By changing the depth of the microscopic oil grooves across the bearings' face, oil is captured more efficiently resulting in a stronger oil film and less friction.
This diagram depicts the internal...
This diagram depicts the internal differences between a standard cartridge fork (left) and the Showa BPF fork (right). Because the BPF basically converts the lower fork tube into the "cartridge", it doesn't need many of the parts necessary in a conventional cartridge fork, such as the internal cylinder and the sub piston, saving weight. Also, because spring preload is now located on the bottom, there no longer needs to be a sleeve running up to the top fork cap. The comparatively huge main piston in the BPF allows substantially more fluid flow through the damping orifices (which can now both be positioned in the main piston instead of separately), which drops fluid pressure and dramatically reduces the tendency for cavitation that causes irregular damping issues.
This computer-generated image...
This computer-generated image shows how Kawasaki engineers altered the new ZX-6R's chassis rigidity for improved rider feedback. The gold-colored front portion shows how the upper engine mounts are now connected directly to the steering head, increasing rigidity in that area. The blue sections represent the larger pressed beam sections that actually provide more lateral flex for better feedback when leaned over. The green portion shows the rear engine mounts that are now part of a one-piece cast component for more rigidity over the previous tabs welded onto an aluminum pipe.
This means that the ZX-6R's pilot has a much wider spread of power to work with, making gear selection far less critical in maintaining speed and cutting down on the number of gearchanges per lap. Peak power arrives at approximately 13,500 rpm, but there's a substantial amount of overrev to 15,500 rpm before acceleration begins to tail off well in advance of the indicated 16,500 rpm redline, allowing you to carry a gear instead of upshifting in many situations. Throttle response was excellent, with a crispness that never bordered on abrupt no matter what rpm we picked up the throttle at. Combine that newfound power with the near-23-pound weight drop and you have the makings of a serious contender for 600 class honors.
Thankfully the ZX-6R's brakes are easily up to the task of slowing the Kawasaki's increased speed. Power, progressiveness, and feel were superb, with very little degradation in performance even after numerous laps on the very demanding confines of the Autopolis circuit. Complementing the impressive brakes is the 6R's very efficient ramp-type slipper clutch that permits downshifts without throttle blipping during very aggressive braking, allowing the rider to more accurately and consistently apply pressure to the brake lever.
We Have A Contendah
After a few years of fiddling with limited production racing homologation special 600s and oversize-displacement middleweights, Kawasaki has returned to its roots-remember, it was the company that really started the 600 class when it debuted the original Ninja 600R in 1985-with a cutting-edge, take-no-prisoners 600. The new ZX-6R addresses all of the previous generation's weaknesses in full (and then some), resulting in a middleweight that will surely be vying for top honors in our next 600-class comparison. With most of the competition only undergoing very minor alterations, this should make for a very interesting shootout. Stay tuned.
'09 Kawasaki ZX-6R
MSRP: $9799/$9999 (Monster Energy edition)
Type: Liquid-cooled, 4-stroke, DOHC inline four-cylinder
Bore x stroke: 67.0 x 42.5mm
Compression ratio: 13.3:1
Induction: Keihin EFI, 38mm throttle bodies, dual injectors/cyl.
Front tire: 120/70ZR-17 Bridgestone BT-016F
Rear tire: 180/55ZR-17 Bridgestone BT-016R
Rake/trail: 24 deg./4.0 inches (103mm)
Wheelbase: 55.1 inches (1400mm)
Seat height: 32.0 inches (815mm)
Fuel capacity: 4.5 gal. (17L)
Claimed wet weight: 421 lb. (191kg)
The new Keihin EFI now uses...
The new Keihin EFI now uses round primary throttle plates 10mm farther away from the oval secondary throttle plates above for improved throttle response. Note the shrouds over the secondary injectors in the airbox lid, in order to shield them from the turbulence resulting from their closer positioning to the intake funnels.
Redesigned intake and exhaust...
Redesigned intake and exhaust ports work with the revised throttle bodies and airbox/ram-air intake for improved low-end and midrange power.
The ZX-6R's ignition "stick...
The ZX-6R's ignition "stick coils" integrated into the spark plug caps feature rare earth magnets that help boost spark output by 12 percent for improved combustion efficiency.
Like the current ZX-10R swingarm,...
Like the current ZX-10R swingarm, the new ZX-6R's unit is made from pressed aluminum sheet beams on each side welded to die-cast pivot/shock mount section.
New pistons feature reshaped...
New pistons feature reshaped crowns for more efficient combustion, moly coating on the reshaped skirts for smoother break-in, and piston rings with less tension to cut internal friction.
Camshafts are now made from...
Camshafts are now made from chromoly steel for a weight savings of approximately 400 grams. Improved surface nitriding of the cam faces and more durable tappets/buckets allow more aggressive cam profiles.
The redesigned ram-air duct...
The redesigned ram-air duct leading through the steering head now doubles as the support for the upper fairing and mirrors, eliminating the previous bracketry and saving weight.
Because the rear subframe...
Because the rear subframe no longer has to support the weight of an underseat exhaust, the section is now two separate precision die-cast aluminum pieces that are much lighter.
New magnesium engine covers...
New magnesium engine covers cut weight, while removable internal noise dampers such as this one inside the clutch cover drop additional weight for racing.