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Kawasaki Ninja ZX-6R Comparison

Monday, May 19, 2008
This year the 2008 Ninja ZX-6R returns to the fray with no significant updates but it has a nice trophy to stick on the mantle and a permanent place in the AMA record books.
Engine: 599cc Inline-Four
Bore x Stroke: 67mm x 42.5mm
Horsepower: 101.6 hp @ 12,700 rpm
Torque: 43.5 lb-ft @ 11,900 rpm
Weight: 428.5 lbs w/fuel, 401.5 lbs w/o fuel
Power to Weight Ratio: 0.24
Wheelbase: 55.3 in. Rake: 25° Trail: 4.3 in.
Seat Height: 32.3 in.
Exhaust dB at 5000 rpm: 83
Measured MPG: 37.3
MSRP: $9099
2008 Kawasaki Ninja ZX-6R

Last year Kawasaki overcame a disappointing finish in Supersport Shootout V and went on to claim the 2007 AMA Supersport championship, proving that you never know what's going to happen when you get inside these motorcycles and uncover their true potential. This year the 2008 Ninja ZX-6R returns to the fray with no significant updates but it has a nice trophy to stick on the mantle and a permanent place in the AMA record books. Kawasaki brings to the shootout one of the most neutral chassis in the middleweight class with a great transmission and spacious ergonomics for our taller riders. The way to look at the Kawasaki is from the angle that this bike, like the R6, is a racebike bottled up in street accoutrements and those restrictions hold it back in some of the key performance challenges we subject these supersport motorcycles to during a month of rigorous testing.

A reoccurring theme with the track performance of the Ninja Six is that it is a competent motorcycle with a high-revving powerplant that feels down on power compared to the other bikes in this test. Rumor has it that the ZX-6R is one of the few bikes in the comparison that meets current sound emission standards, so we performed an unofficial sound test using the techniques implemented by California Highway Patrol to determine if there is any truth to the paddock gossip. What we discovered is the ZX is the quietest bike in the bunch, ringing in at a reserved 80 dB at 5000 rpm, 5 dB less than the Honda and Suzuki and 9 dB less than the Ducati and Yamaha. If only there was a way to uncork the ZX-6R hmm.

After running these six sleds on our Dynojet 200i, the Ninja finishes last in outright horsepower production with 101.6 hp at 12,700 rpm, eight ponies down on the R6 but a mere three ponies down versus the popular 675 mill. Peak power comes on sooner than the other three Japanese bikes, but its 43.5 lb-ft of torque at 11,900 rpm arrives later than either the CBR or GSX-R while feeling like it tapers off sooner than the R6 and CBR on the track. It's a matter of tough love for Kawasaki, which doesn't suffer from a huge horsepower disadvantage on paper but feels like it is slower in actual application. The accompanying dyno charts show that the green line is regularly at the bottom of the graph. Look close and you see that it intersects with the class horsepower king R6 until about 13 grand. That's when the other bikes blow past and keep on building power. Fortunately the transmission and gearing are perfect for Infineon and Thunderhill because as the lap times show, the Ninja is never far off the pace.

During our Superpole session, the Kawasaki finishes at or near the bottom on both of our rider's lap charts, 1.8-seconds behind the Suzuki on Earnest's list but fifth-fastest and only 0.33-seconds behind the speedy Gixxer Six on Hutch's. With an emphasis on these lap times as a metric in this review, this scenario and the low peak power figures had the Ninja playing catch-up the rest of test.

"The motor is a little soft and seems to send a lot of vibes in the upper rev range," explains Mike E. "The thing's got a really nice transmission, it handles well and offers great feedback from the front end. It's a good looking bike too. I love the black footpegs and levers and it has decent ergos for a tall guy. Just needs a little more power."

Brakes and suspension are decent and it looks good  especially in the Kawasaki Lime Green livery of our test unit.
As Roger Hayden and Jamie Hacking proved in the AMA Supersport class last year, the Kawasaki ZX-6R is a very fast machine with plenty of podium potential.
Subjective rider scoring reveals that the majority of the testers feel the Ninja's chassis, in regards to both turn-in and stability, is one of the strong suits the Kawasaki has in its arsenal and, as you can tell, the big daddies of the group all feel the ZX fit them the best. In the remaining track categories, the Kawasaki falls victim to an array of mid-pack results that, when coupled with the highest weight (407 lbs without fuel), lower lap times and horsepower numbers, keeps it from having a shot at the title. But as it proved last year - that doesn't mean squat once the light goes green.

"First, sitting on the bike it feels the roomiest for me," says 6'3" Call. "Being that I am a bigger rider, I have to use the revs a lot to get these little bikes to move and what I found was that it has a lot of vibration between 14-16 grand, plus it feels like it flattens out on top and peters out. The bars are nice and wide. The brakes are good and strong. Suspension is really good for stock; maybe a bit soft in the rear. It's very stable though and it doesn't do anything weird. Its flickability in the chicanes is nearly effortless too. It doesn't have a lot of gyro so it handles real good in the corners."

Cory is not the only racer to praise the Kawasaki's ability to navigate the twists and turns of a road course because Jimmy Moore also found the ZX to his liking. No surprise that he has a soft spot for the 6R considering one of his memorable journeys include racing one in the treacherous 2007 Macau Grand Prix road race. It was there that he discovered the joy of the agile ZX.

"This is the sleeper bike in the bunch in my opinion. This bike is really fun to ride and feels as though it has loads of potential. I was lucky enough to have ridden the AVIVA full factory version of this bike, from the British National Championship, at the Macau street race in China last year and it was easily the best 600 I have ever been on," reminisces Jimmy Moore.

Out on the open roads, the roomy ZX-6R was one of the favorite bikes for our taller riders. It also fared well in the objective scoring on the street test, including the second-best fuel economy at 37.2 mpg, trailing only the 38 mpg Yamaha. Ringing in at a budget-friendly $9099, the ZX-6R is the second-best bargain of the bunch behind the Triumph. The Ninja also scores high in fit and finish with its nifty instrument cluster, attention to detail and the blacked-out treatment on the levers, footpegs and exposed brackets combining to make this one of the most-clean designs in the test.

After running these six sleds on our Dynojet 200i  the Ninja finishes last in outright horsepower production with 101.6 hp at 12 700 rpm  eight ponies down on the R6 but a mere three ponies down versus the popular 675 mill.
One of the high points in the ZX-6R package is turn-in and stability while cornering.
"Without a doubt the Kawasaki is a fun bike to ride," writes Waheed, "and if you didn't ride it back-to-back with the other bikes you wouldn't be losing out on anything. However, since it is down a bit on power, it makes the ride seem not as exciting as the other bikes."

Considered on its own, the Kawasaki ZX-6R is an amazing motorcycle that feels lighter and faster than it actually is. Brakes and suspension are decent and it looks good, especially in the Kawasaki Lime Green livery of our test unit. The problem arises from the comparison, which exposes some of the bike's deficiencies which in the end comes down to meeting emission standards. Pull off the wire-swap trick and suddenly the ZX is in the hunt for a higher position in the final standings.

Kawasaki ZX-6R - Rider Notepads:
Neutral turn-in not as quick as R6 but more stable.
Chassis feels long and stable like the 848.
Ergos feel big.
Motor feels soft.
Excellent transmission.
Styling is great.
Vibrates at high rpm.
Front-end inspires confidence.
Flattens out too quick up top.
Bars are nice and wide.

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2008 Kawasaki ZX-6R Track Video
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Kawasaki ZX-6R Highs & Lows
Highs
  • Comfortable Ergos
  • High-speed Stability
  • Smooth Throttle
Lows
  • Underachieving Motor
  • Vibration on Top End
  • Lack of Character

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