Kawasaki ZX-6R Ninja


Make Model

Kawasaki ZX-6R




Four stroke, transverse four cylinder, DOHC, 4 valves per cylinder


599 cc / 36.6 cub in
Bore x Stroke 67 x 42.5 mm
Compression Ratio 13.9:1
Cooling System Liquid cooled


DFI® with four 38mm Keihin throttle bodies, oval sub-throttles, two injectors per throttle body
Lubrication Wet sump


TCBI with Digital advance 


Spark Plug NGK, CR 9 E
Motor Oil Synthetic, 10-60

Max Power

91.9 kW /125 hp @ 14000 rpm

Max Torque

66 Nm / 6.73 kgf-m / 48.7 lb-ft @ 11700 rpm
Clutch Wet, multiple discs, cable operated


6 Speed 
Final Drive X-ring chain
Frame Perimeter, pressed-aluminium

Front Suspension

41 mm inverted cartridge fork with top-out springs, stepless rebound damping, stepless compression damping, fully-adjustable spring preload
Front Wheel Travel 120 mm / 4.5 in

Rear Suspension

Bottom-Link Uni-Trak® with gas-charged shock, top-out spring and pillow ball upper mount, dual-range (high/low-speed) stepless compression damping, 25-way Adjustable rebound damping, fully-adjustable spring preload
Rear Wheel Travel 133 mm / 5.2 in

Front Brakes

2 x 300mm discs, 4 piston calipers

Rear Brakes

Single 210mm disc, 1 piston caliper

Front Tyre

120/65 ZR17

Rear Tyre

180/55 ZR17
Rake 25°
Trail 109 mm / 4.3 in

Length 2105 mm / 2.8 in

Width     720 mm  / 28.2 in

Height  1125 mm / 44.2 in

Wheelbase 1405 mm / 55.3 in.
Seat Height  820 mm / 32.3 in.


167 kg / 368 lbs
Wet-Weight 190 kg / 418 lbs

Fuel Capacity 

17 Litres / 4.5 US gal

Standing ¼ Mile  

11.2 sec

Top Speed

252.1 km/h / 156.4 mph


The natural choice for your inner racer

A true race winner, the Ninja® ZX™-6R sportbike captured a 1-2 finish in the 2007 Daytona 200 and placed 1-2 in the 2007 AMA Supersport championship, thanks to a merger of 600-class power and Grand Prix handling. The result is an exciting racetrack weapon capable of cornering speeds previously unknown to the middleweight class while retaining the wide spread of power that is pure Ninja.

To deliver the performance required in the demanding racetrack environ, the Ninja ZX-6R’s ultra-high-rpm 599cc four-cylinder engine cranks out a fat powerband with a linear torque curve and hard-hitting acceleration across the entire rev range. Its impressive healthy mid-range torque and over-rev capability are pure race bike, allowing riders to stay on the gas where lower-revving machines are forced back off and shift.

The Ninja ZX-6R’s engine was specially designed for minimal internal friction, so it is more responsive and allows the rider to easily modify cornering lines with minor throttle adjustments. Utilizing stronger, stiffer and more compact engine components than its predecessors resulted in a slim and compact engine and chassis. Its racing heritage also includes a close-ratio cassette transmission that makes it easy to keep the ZX-6R screaming at its horsepower peak and a slipper clutch for quick downshifts that don’t upset the rest of the chassis.

A compact, lightweight chassis design permits the Ninja ZX-6R to make a fast entry –enhanced by the slipper clutch and powerful radial-mounted front brake calipers –and maintain more cornering speed throughout the turn.

The frame and swingarm were developed with an ideal balance of rigidity, so the bike responds instantly and precisely to the rider’s every command. Mass centralization, engine mount locations and a variety of other factors were optimized to help its instant turn-in characteristics. Once in the turn, the Ninja ZX-6R holds a line with precision and tracks through the apex as if it were on rails. Completing this track-biased package are fully-adjustable front and rear suspension units.

All these features mean very accurate chassis feedback, with the ZX-6R communicating every move directly to the rider. The machine responds more precisely and predictably to control inputs and shifts in body weight. The result is a motorcycle that becomes one with the rider.

The entire package of frame, suspension, engine and bodywork enhances the ZX-6R’s fun-to-ride factor while supplying the high-performance power of a 600cc Supersport racer and the nimble handling of a small-displacement GP machine. The results are faster cornering speeds, quicker lap times and even more worried looks on the competition’s faces. So let the opposition compromise performance for rider-friendliness; the Ninja ZX-6R is a pure expression of Kawasaki’s racing philosophy and is designed to take home trophies.

Key Features

- Incredible power-to-weight ratio

- Race-oriented performance

- Track-tuned handling

- Aggressive aerodynamic styling

High-Revving 599cc Four-Cylinder, DOHC Engine

- Compact, narrow and lightweight design

- Tri-axis crankshaft and transmission shaft layout optimizes the engine’s center of gravity, reduces pitch changes during heavy braking and gives the rider more-accurate feedback from the chassis

- Light and strong forged pistons

- Narrow engine design gives excellent ground clearance


Four-Valve Cylinder Head

- Low cylinder head height with compact valve train

- Intake ports and coolant passages developed using flow analysis for efficient cylinder filling, more power, and maximum cooling efficiency

- Forged sintered aluminum spring retainers are half the weight of steel retainers and allow higher rpm




Ram Air Induction

- Central ram air duct offers a straighter path to the airbox for maximum intake efficiency and provides the mounting surface for the instrument panel, eliminating brackets and weight

- Flow analysis used to design efficient ducts to the airbox that also prevent water from reaching the air filter

- Compact airbox and air cleaner are highly efficient and contribute to the minimal riding position


Digital Fuel Injection

- 38mm throttle bore helps produce more torque in the mid-range, while short throttle body length delivers good over-rev characteristics

- Ultra-fine atomizing injectors aid combustion efficiency, for better power output and lower fuel consumption

TCBI Ignition with Digital Advance

- High-speed 32-bit ECU processor provides precise engine management

- Spark plug-mounted ignition coils are compact and help reduce weight

Pre-chamber Equipped Under-seat Muffler

- Exhaust header design contributes to improved exhaust efficiency

- Exhaust pre-chamber located below the engine contributes to better mass centralization

- Under-seat silencer is small and light to help mass centralization and allow for a more aerodynamic tailsection

Six-Speed Transmission

- Cassette-type transmission with a racing-style gear stack allows easier trackside ratio changes

- Close ratio transmission increases circuit performance


Racing-Style Slipper Clutch

- Racing-type slipper clutch reduces chassis disturbance when making rapid downshifts

- Optional springs, spring retainers and shims are available to fine-tune the clutch for specific track conditions

Gear Position Sensor

- Gear position sensor gives instant information to the rider, this is especially useful for improving consistency when testing settings on the racetrack

- System is compatible with the semi-automatic shifters (legal in AMA Supersport racing), which temporarily cut ignition to facilitate clutchless shifts at full-throttle

Lightweight Twin-Spar Aluminum Perimeter Frame

- Twin-spar perimeter-type frame is a mix of pressed and cast aluminum components welded together. This combination minimizes frame weight while still providing high strength and stability for responsive handling

- Chassis’s optimum center of gravity makes for easy roll response - particularly important negotiating a series of s-turns or returning to vertical after exiting a corner




Uni-Trak® Rear Suspension

- Uni-Trak® rear suspension system features pillow ball upper mount for a more direct feel and improved feedback

- Compact frame and engine allow a longer swingarm, which makes it easier to control rear wheel powerslides

- Rear shock is fully adjustable for preload, compression and rebound damping. Ride height can be adjusted by adding/removing optional 1mm shims at the upper shock mount

- Equipped with a top-out spring which improves the rear wheel’s ability to follow the road surface when the rear end is light under hard braking

- Small piggyback shock reservoir is designed to save weight

41mm Inverted Cartridge Front Fork

- Fully-adjustable 41mm inverted cartridge fork provides exceptional rigidity

- Equipped with top-out springs so the front wheel better follows the road surface when the front end is light during hard acceleration

- Bottom mounted main fork spring completely submerged in oil, minimizing cavitation and delivering stable suspension performance even under demanding racetrack conditions

- Stiff settings are suitable for track use


Radial Mounted Front Disc Brakes

- Radial mounted four-piston, four-pad front brake calipers improve brake feel over a wider range of operation

- A separate brake pad is used for each piston. Individual pads provide increased cooling efficiency and can absorb more heat without deforming or losing brake feel at the lever than a large single pad, so they maintain consistent brake feel lap after lap

- Petal design brake discs offer excellent cooling and warp resistance


Aerodynamic Bodywork

- Design is the most aerodynamically efficient of any Ninja sportbike available

- Three-piece front fender with light and compact projector beam headlights and integrated front and rear turn signals add up to high aero efficiency

- Small but highly efficient ram air duct

- Exhaust system’s under-engine resonator allows the use of a smaller under-seat muffler, which allows a cleaner tail section further minimizing drag

- Different color panels create a sporty, aggressive image


Riding Position

- Ultra-compact chassis permits a ideal man-machine interface

- Slim fuel tank design makes it easier to grip the tank and seat when hanging off in a turn

Advanced Electronic Instrumentation

- Multifunction odometer, tripmeter, clock and lap timer/stopwatch


Pity the poor engineers of supersport bikes, forced to juggle seemingly contradictory design directives. It's got to look bitchin' but it can't cost too much, and don't forget to make it go around a racetrack quicker than any of its rabid competitors.

Reflect back just 10 years and you'll see the middleweight class composed of bikes that could easily be used for regular commuting or some light touring, with handlebars mounted above the triple-clamps, accommodating footpeg placement and some storage under the seat. Those days, like the hotel TV set of a petulant rock star, are gone out the window. Now a sporting middleweight needs to be the sharpest tool, as a rider shouldn't be forced to ride anything but the pinnacle of sportbike technology - the most capable scalpel extant.

Well, Kawasaki is down with that program. Its new ZX-6R was developed from the beginning on race tires, not the street shoes earlier models wore during gestation.

"This is a full-blown race bike," said Kawasaki's Karl Edmondson during the bike's press introduction at Barber Motorsports Park in Alabama.

And on the hugely fun and wildly undulating 2.3-mile Barber circuit, the new ZX feels kind of like a race bike. It doesn't take many laps to gain a sense of trust, and it responds unequivocally to a rider's inputs. It feels taut and confident, perhaps more so than any previous Kawasaki.

So how'd they do it - make a better bike than the excellent one that came before it - this time?

It all started where they all do: the engine. In this case it's new from the cases up, the first total redesign for Kawi's middleweight in 10 years. For starters, it was left in the dryer a really long time, shrinking 40mm in both length and width; that's getting on close to 2 inches for those not good with the metric system. Its narrowness was made possible by snuggling its four cylinders closer together, while it was shortened by placing its crankshaft, primary drive and countershaft gears in a tight triangular arrangement like its classmates.

Inside this new architecture reside some reminders of last year's ZX-6RR motor, the 599cc one built for racing. They share the same bore and stroke (67.0mm x 42.5mm), as do the rest of the class challengers. There will be no more cries of "cheater bike!" because Kawasaki will no longer build the 636cc version it's had in the lineup since 2003.

Like before, a set of oval 38mm throttle bodies mix air and fuel, but they are now 8mm shorter which might offer a high-rpm benefit. Like the 6RR, the intake ports are polished for cleaner, faster flow to the 1.5mm larger intake valves (26.5mm) operated by new cam profiles. The forged, short-skirt pistons are lighter, and even the piston pins weigh less, as do the forged- and sintered-aluminum valve spring retainers that reduce weight by half compared to steel pieces. The intake mixture is squeezed at a lofty 13.3:1 compression ratio, which seemed high until I noticed the 13.9:1 ratio of the old 6RR. Exhaust is routed though header pipes that curve sexily before routed into the under-engine pre-muffler/catalyzer; this allows the undertail muffler to be smaller for a tidier tailsection.

So, smaller engine, smaller bike, right? Er, no actually. It's taller and wider, though just fractionally, and it's longer by 1.6 inch. And the new bike must've been born shortly after Thanksgiving, as the specs say it weighs 6 lbs more than last year. If true, it would put the ZX's weight at about 402 lbs with its tank empty. That's still lighter than Suzuki's Gixxer 600, but it might be as much as 19 lbs more than the radically slimmed down '07 Honda CBR600RR.

You'd never guess any of this when you sit on the ZX, as it's slimmer though the middle and a rider sits closer to the front wheel, giving the bike a more compact feel. Bars are closer to the rider and lower. It's a racier place to do business, with footpegs that are placed closer together thanks to that narrower motor.

So let's fire it up, then. Hopefully your first experience on the Zixxer isn't in the 23-degree weather that greeted me for my debut session on a track I hadn't seen before. Nevertheless, I had a job to do. Thankfully our bikes had tire warmers ("Uh, could I stick one of those in my pants.?"), and the Bridgestone BT002 Pros proved to have surprisingly good grip even in these cold conditions. The "Pro" version of the 002s debuted earlier this year, and the medium-compounds we rode on at 28 psi received rosy comments from the assembled scribblers.

Kawasaki's PR literature claims the new 6R "churns out way more midrange torque than its predecessors," but whoever wrote that must not have ridden the burly ZX-636. Perhaps they were referring to the old 6RR that was quite wimpy at lower revs. Still, this new bike doesn't feel especially grunty halfway around the tachometer. It sings up top, though, pulling strongly from 10,000 rpm to its 12,500-rpm peak but with room to spare to its 16,500 redline, again same as the old 6RR.

A glance at the spec charts offers what might be seen as a worrying sign to number crunchers. This '07 ZX is rated at 116.4 hp. Not only is that down from the 124-pony claim of the 636cc 6R, it's also virtually identical to last year's 599cc ZX-6RR.

(As with the previous gen ZX-6R, ECU tuning on U.S. and Canadian models has strangled the top-end power by closing the exhaust powervalve at high revs to meet noise regulations. The European model makes a claimed 123.3 ponies, a healthy boost of almost 7, plus it allows the engine to pull stronger up top, making its peak power 1500 rpm higher. This might be sad, but only if we didn't know how to trick the ECU to default to the Euro spec settings with a free 5-minute mod you can read about here.)

Is this progress? Yes, according to the ZX's engine designer, Takahiro Ono. He notes that getting around a racetrack quickly isn't just a matter of how much power you have, but how early you can dial it on and how well you can put it to the pavement. As an example, he related to me of how the new 800cc MotoGP bikes have been breaking lap records in pre-season testing despite having 24% less displacement than their 990cc forbears. Closer to home, Kawi's engineers claim the '07 bike can lap Kawi's Autopolis racetrack a good 2 seconds quicker than the old RR and at least 3 seconds quicker than the ZX-636.

Whether that's true or not is difficult to say from my seat, but I can attest to a highly cooperative machine, and it's hard to imagine a better mount for learning, then strafing, the hills of the technical BMP. Throttle response is super smooth, with none of the on/off throttle abruptness we despise. Kawi says the ZX's "modified flywheel mass contributes to increased traction," which we'll take to mean that it has more of it, and the theory seems to work.

Also aiding the rider is the ZX's clutch and transmission. First off, kudos must go to the excellent slipper clutch - it's as good as any OEM unit I've tried. Bang a quick and sloppy downshift into Turn 1 without caring about details like rpm, and the back-torque-limiting clutch simply allows revs to match wheel speed. In addition, its amount of slip can be fine-tuned by Kawi's optional race kit pieces. Also available are two optional gear sets for the cassette-style transmission that enables trackside internal gearing changes, the only middleweight with this racer-desirable component. Shift action is light on the ZX, though it can get hung up if you're not careful to let the lever drop all the way after an upshift. Gear ratios are closely spaced, which worked well at the racetrack, though it may not be as optimal for the street.

But where the new 6R really shines is in the corners. Kawasaki pumps up the fact that the bike's chief development rider, Tomomi Manako, is a former 125cc GP rider, and this has supposedly resulted in a bike that boasts higher corner-entrance and mid-corner speeds. The chassis geometry points to nothing unusual, using the same 25.0-degree rake as last year's 6R and a scant 4mm increase in trail. Its wheelbase is up 0.6 inch over the old 636 and nearly identical to the Double-R version at 55.3 inches.

In the morning I was enjoying the assuring stability of the bike, glad that a steering damper was on board to quell any headshake. It was a short while later in the pits when I confirmed that there is no such component on the 6R, a real testament to the core quality of the chassis. Still, fighting with the bars over one of Barber's many rises can induce a minor bar wag, and Kawi offers a ZX-10R-style Ohlins steering damper through its race kit catalog for those who want the insurance it offers.

Some manufacturers like to flaunt percentage changes in torsional or lateral rigidity of their frames, but Kawi is more demure by coyly saying, "The frame's rigidity balance was completely revised to enable the chassis to easily handle mid-corner surface imperfections without upsetting the bike." Reading between the lines, they've probably reduced the lateral rigidity.

The front end provides the kind of direct response that entices a rider to turn it in a little quicker and lean it in a little further. This new ZX provides communication in bigger doses than any other Kawasaki. From a strictly handling perspective, this thing is going to run at or near the sharp end of the supersport field. It takes a fair bit of prodding before pegs are dragged, and ground clearance is certainly not an issue for any street riding.

A critical role in the handling equation is the suspension. The ZX still uses a 41mm inverted fork up front, but its spring is now located at its bottom, fully ensconced by oil to reduce oil cavitation. At the rear, the shock's linkage now uses what Team Green call "pillow balls" where standard bushings are usually found (Insert lewd and juvenile joke here). Both ends are adjustable for preload and compression and rebound damping, and the shock gets the bonus of having its compression adjustments separated into high-speed and low-speed.

It seems like pillow balls are a good thing to have, as feedback from the rear end is generous. The front end is just as good. The braking bumps entering Barber's Turn 5 were sucked up so nicely that I had to be told about the ripples before I noticed them.

Let's also give praise to the Ninja's brakes. These are the same 4-piston, 4-pad radial-mount calipers actuated by a radial-pump master cylinder we've enjoyed for the past two years of ZX-6s, but its 300mm rotors are now 6mm (from 5.5) thick to better shed heat without going to a larger-diameter disc. Ample power, no fade, and best of all, plenty of feedback. Zero complaints here.

And we can't complain about the ZX's hard-to-read tach any longer, as it's now a simple white-faced analog rev counter with red numbers that take just a moment to assimilate. An unmistakable yellow shift light in the upper-left quadrant can be programmed to illuminate at whatever rpm you choose. I was happy to hear the ZX had a gear-position indicator, as it's been our experience that they're handy for riders of all talent levels, but Kawi just couldn't give us a perfect set of gauges. I couldn't believe my eyes when I saw the 6R's indicator, as it's so small that it's useless. Well, it may be readable on an open highway in Nebraska, but certainly not when you're screaming in to Barber's Turn 1 at a-buck-thirty.

Other than that minor faux pas, our only reservation with the '07 ZX-6R is with what seems to be a top-heavy powerband. Kawi talks about "a mile-wide" spread of power, but that might be a bit optimistic. It felt to me as if it might fall between the reasonable GSX-R and the Yamaha R6 screamer. From what Kenny tells me, new CBR600RR is in contention for the most desirable powerband of the 600s.

With its $8999 MSRP, the ZX is $300-$400 cheaper than the R6 and $500 less than the CBR (the GSX-R is just $8899). It was only a few years ago that middleweights crossed the $8000 threshold, and now they're approaching $10K!

As for which bike is going to be the best overall supersport contender, it's too early to tell. In the Kawi's favor is its stellar handling and reasonable price tag.

Source Motorcycle-USA