Great nations develop a reputation not only for its populace and distinctive culture but also for the goods it produces. For the French it’s their bubbly. The Germans are acknowledged for their precision engineered automobiles, while the Chinese are recognized for cranking out all kinds of affordable goods we use daily. The realm of motorcycling is no different; and for aficionados of affordable, quality, high-performance sportbikes there is only one country that comes to mind - Japan.
Although a good majority of motorcycles pumped out from this beautiful island country are engineered for comfort and convenience; supersport replica-racers are built for one purpose - to get from point A to point B as fast as possible - whether it’s your favorite backroad or the racetrack.
So this year, Kawasaki ups the middleweight-class ante by releasing a revamped ZX-6R designed to trounce the competition. And what better place on earth to experience Team Green’s cutting edge 600 than on the very same 20-turn, 2-mile road course which it was born on - Kawasaki’s own Autopolis International Racing Course.
Ingredients of Speed
"Every year the Big Four find a way to trim weight off their sportbike lineups. This year's supersport Ninja in no different."
Your parents always said it’s what’s inside that counts; and apparently Japanese families are no different. Thus engineers introduced a substantially lighter, more powerful 599cc Inline-Four. Engine vitals like its 67 x 42.5mm bore/stroke and 13.3:1 compression ratio remain unchanged. What has changed, however, are the camshafts, which are nearly one pound lighter and coated with a more durable outer coating, revised cylinder porting and new friction-reducing pistons for improved performance, especially in the mid-range.
Above, cylindrical aluminum guides direct fuel spray into 10mm taller dual-bore velocity stacks that utilize inlets at two fixed lengths, thereby optimizing engine fueling during mid-and-high rpm engine loads. More powerful ignition coils are said to improve combustion efficiency.
Other weight saving adaptations includes narrower transmission gears and a revised shift dog shape. Oil pump and starter gears have also been trimmed down, while engine covers are now manufactured out of magnesium and feature removable noise-reducing pads on the inside. Primary fuel-injector mounting plate, relocated head pads, and a smaller coolant reservoir round out the changes and net an additional four-pound weight reduction.
In the chassis department, the new Ninja 6 benefits from an updated frame, tuned for added lateral flex within the frame spars and increased rigidity in the steering stem area and at the rear engine cross-mount. Steering head angle has been reduced by one notch (from 25-degrees) in order to sharpen steering. Engineers complemented this change by tilting the engine upwards around the countershaft sprocket, thereby raising the engine’s center of gravity and aiding the ability to change direction.
A beefier boomerang-shaped swingarm was designed for optimum rigidity balance, working together with the frame to give the rider a more accurate feel as to what’s happening at the business-end of the rear Bridgestone tire. A two-piece die-cast aluminum subframe further contributes to the bikes overall reduced weight and slims down the back end of the motorcycle.
"A 41mm inverted Showa fork uses BPF (Big Piston Fork) technology - the first of its kind on a production sportbike."
Due to the increased space made available by the relocation of the exhaust, the gas-charged rear shock has been repositioned and features improved internal damping characteristics. The shock retains four-way adjustability for spring preload, high/low-speed compression and rebound damping.
Technology Breeds Performance
The rev-limiter is just about to interrupt as you begin to slow for Turn 1. Pop up from behind the still comfortable at speed large windscreen and promptly get into the front brake lever. Heavy braking areas such as this make it clear just how well the BPF fork works. Load is transferred to the front wheel in a smoother, far more controlled fashion. Bang down three gear s (from fifth) in rapid succession and the engine responds by continuing to zing in the upper echelon of the tachometer as you get into the corner.
Just as soon as you clip the apex, pin the throttle and the bike drifts out to the left, just clipping the candy-colored curbing. The track slowly veers to the right as you pass through Turn 2 and you’re full-on accelerating through fourth gear.
"Pushing the front end on the new Ninja at Autopolis, the BPF fork proves its worth with smooth stability and feedback."
Back in second gear, swing wide for the entrance of Turn 4. With a knee on the deck, run the bike wide before cutting back in for Turn 5. Back on the binders and trail braking into Turn 6, the right foot peg feeler gently scrapes the pavement as you hit the apex and begin accelerating into Turn 7 - demonstrating just how much ground clearance the bike has. As you exit, the rear end gently squirms, signaling that the race-spec Bridgestone BT-003 rubber is looking for grip. Still leaned over, grab an upshift before diving into Turn 8/9. You’re fully cranked on your side as you accelerate uphill into Turn 10, the chassis keeping you well aware of just how hard you can push the bike.
Accelerating thru fourth gear you’d appreciate the extra velocity provided by a liter-class machine, yet the ZX-6R’s mid-range snap will surprise, as it’s robust for a 600 - and a vast improvement over its predecessor. Even more notable perhaps is the top end that just won’t quit. Where last year’s bike would run out of steam well before redline, the engine in ‘09 never says die. Even when you do hit the rev-limiter the cut-out is soft, so acceleration doesn’t feel like it is ending abruptly.
As you enter the hairpin, trail brake hard until you clip the inside candy-painted apex. Here you’ll be amazed by the direct amount of feel provided by the front brakes, which allows you to scrub speed at considerable lean with absolute confidence.
You have momentum working with you as you gain speed downhill - the tachometer needle swings wildly along with the incessant yellow flash of the shift light as you bang third, followed by fourth gear - descending towards the right hand, motocross-style berm - aka Turn 12. You can go really deep, carrying a high amount of speed into this corner, so it’s important not to go gangbuster on the brakes; instead brake swiftly, downshift, and toss the bike into the corner. On this type of fast entry corner you can appreciate how solid and unflappable the chassis feels.
Stay to the outside as you exit, accelerating hard, then flick the bike onto its right side into Turn 13, which gradually tightens into Turn 14. In sections like this, where you’re turning the bike quickly from side-to-side, you’ll appreciate just how easily the bike initiates a turn. There are a number of different line choices in this portion of the track, but for us, we’d hug the inside of Turn 15, then stay to the outside and turn into T16 at the last possible second, all while being sure to keep your momentum as you’re again climbing uphill. Here you’ll notice the crisp and instantaneous throttle response which really helps you stay in control when you’re between gears in a section of track.
As you pass underneath the bridge and enter Turn 18, you’re again on the front brakes while dipping the bike to the left. Accelerate as you drive out, then right before you enter Turn 19, downshift into second gear. The engine will be zinging as you carve right. Muscle the bike left without letting off the gas in order to get a strong drive out of the final chicane-style turn. Back on the front straightaway you’re again in full-tuck, rowing through the precise-feeling, 6-speed, cassette-type gearbox.
"The 2009 Kawasaki ZX-6R is improved and looking to knock off the Honda CBR600R and Yamaha YZ-FR6 in the upcoming Motorcycle USA Supersport Shootout."
After two days and seven 20-minute sessions aboard the new ZX-6R, we came away impressed. All of the troubles of last year’s bike - engine power, heaviness, and then some - have been addressed, while the positive attributes like its phenomenal brakes, excellent throttle response, and stable chassis have remained intact.
So will the $9799 ZX-6R have what it takes to ace Honda’s CBR600RR on the streets and Yamaha’s YZF-R6 on the racetrack? We know this - it’s going to be close… Really close.
Engine: 599cc liquid-cooled Inline-Four, DOHC
Bore x Stroke: 67 x 42.5mm
Compression Ratio: 13.3:1
Fueling: fuel-injection, 38mm Keihin throttle bodies
Horsepower: 124.3 hp @ 13,500 rpm (claimed)
Torque: 49.2 lb-ft @ 11,800 rpm (claimed)
Transmission: 6-speed cassette-type
Clutch: Wet, slipper-action w/ cable actuation
Front Suspension: 41mm Showa BPF with adjustable compression damping, rebound damping and spring preload; 4.72 in. travel
Rear Suspension: Uni-Trak equipped gas charged shock with adjustable high/low speed compression damping, rebound damping and spring preload; 5.24 in. travel
Front Brakes: Dual 300mm petal discs, radial-mount 4-piston Nissin calipers
Rear Brake: Single 220mm petal disc, single-piston Tokico caliper
Tires: Bridgestone Battlax BT-016 120/70R17, 180/55R17
Curb Weight: 421 lbs (claimed, ready to ride)
Wheelbase: 55.1 in. Rake: 24 deg. Trail: 103mm
Seat Height: 32.1 in.
Fuel Tank: 4.5 gal.