Fast, tight and light, the ZX-10R is Kawasaki's most potent sportbike yet. From the March 2004 issue of Motorcyclist Magazine. By Aaron P. Frank
Photos By Kinney Jones And Tom Riles
Midway through my first "Meanie Greenie Ninjatini," I noticed there was no motorcycle in the fifth-floor reception suite of Miami's posh Mandarin Oriental hotel. How odd. The entire North American motopress was gathered here to mark the release of the new-from-the-tire-tread-up ZX-10R, and save for a few dimly lit photos on the wall, said bike was nowhere to be found. Instead, there was a television monitor playing an ancient video loop from the introduction of Kawasaki's very first Ninja -- the 1984 ZX900 released at Laguna Seca 20 years earlier.
The message was clear: The motorcycle in the shadowy posters, a bike we wouldn't lay eyes on until the next morning, was to be the most important Kawasaki sportbike of the past two decades. Anticipation makes the heart grow fonder? We got our answer early the next morning when we disembarked at Homestead Raceway and entered the pit garages, where more than a dozen ZX-10Rs were lined up and waiting. Full of anticipation from the previous night, we suited up and climbed aboard, expecting something radical. The first ride didn't disappoint.
Small. Svelte. Miniscule. Elfin. Straddling the ZX-10R, you are taken by just how tiny the motorcycle is -- this is no gentlemanly giant, such as the old ZX-9R. The night before, various Kawasaki folks had trotted out the old "literbike power in a 600-sized chassis" saw, but this time it was true. Park the ZX-10R side by side with the latest ZX-6R, and the 10R tucks neatly into the Six R's shadow. Frontal area is actually smaller than the 6R's, and overall width is nearly the same thanks to the 10R's ultra-compact engine and unique "backbone/twin-beam" frame, with main rails that arch over, not around, the cylinder head. The frame is especially narrow at the waist -- the back of the fuel tank is just six inches wide -- so the ZX-10R seems to disappear between your knees.
Chassis geometry is bleeding-edge and inspired by the ZX-RR MotoGP racer (see Alan Cathcart's riding impression). The new engine was moved almost an inch aft and more than an inch lower in the new frame relative to the 9R, and the front-axle centerline is now an inch closer to the swingarm pivot, with 102mm of trail to keep the 24-degree rake angle from allowing things to get twitchy. Most of the distance shaved up front is tacked onto the longer, gull-wing-type swingarm to better put down power and -- in theory -- keep the front end grounded. Even with the longer swingarm, the ZX-10R's wheelbase is listed at just 54.5 inches -- 0.6 inches shorter than the ZX-6R's.
The compact mainframe helps put the low clip-ons within easy reach and positions your upper body well over the front end for extra confidence on the track. Although the cockpit is close-quartered, it's not cramped -- a good thing, as you need to hug the concave tank quite tightly to get behind the short, aerodynamically sculpted fairing at speed.
Such diminutiveness is brought to you by the new, compact 998cc engine. Key features include a "tri-axis" gearbox design (with stacked input and output shafts) that reduces engine length and a tiny generator tucked between the cylinder bank and output shaft to reduce engine width. A one-piece cylinder and crankcase assembly cuts two pounds and increases rigidity, and magnesium engine covers save a few more ounces. Inside the cases, extensive "slosh analysis" (excuse the engineer-ese) was applied to reduce windage losses and oil temperatures, the latter further minimized by a liquid-cooled oil cooler adjacent to the oil filter.
Rapping the throttle in the pit garage reveals an especially quick-revving, short-stroke (76 x 55mm bore x stroke) four. A chrome/composite bore coating cuts internal friction, as do machined-from-billet cams (a half-pound lighter than cast sticks), forged, short-skirt pistons and oval-section valve springs with aluminum retainers that help the motor survive its 13,000-rpm redline -- 1350 rpm higher than the CBR1000RR's.
A centrally located ram-air duct pressurizes the airbox, and fuel is force-fed to compact combustion chambers by a quartet of 43mm, dual-valve throttle bodies fitted with new, fine-atomizing injectors (the droplets are said to measure 70 microns long, compared with 120 microns from conventional injectors) for smooth, step-free power delivery. At the other end of the combustion pathway is a titanium 4-into-1 exhaust system complete with a de rigueur butterfly valve at the collector and an aluminum-sheathed, titanium-cored oval muffler.
Out on the track the ZX-10R is stinky fast, shooting the front wheel skyward exiting first- and second-gear corners and spinning the rear wheel everywhere else if you're not gentle with the go-handle. Kawasaki claims 172 horsepower before ram air, and we're guessing approximately 155 at the rear wheel -- a touch more than last year's GSX-R1000, in other words. (Editor's note: It turns out this was slightly conservative, as our dyno showed.) Power comes on strong down at 4000 rpm and builds smoothly all the way to the 11,500-rpm power peak, with no perceptible fall-off on the overrev. No rheostat analogies here -- the new Ninja's engine character is utterly thrilling, ripping through the revs with a very unliterbike-like alacrity and a typically raspy Kawasaki exhaust note that impersonates Schumacher's F2003-GA F-1 Ferrari, adding to the delicious chaos.
Eager, instantaneous and initially hair-raising are likewise good ways to describe the 10R's handling. Kawasaki unapologetically presents the ZX-10R as the ultimate track bike, designed (according to the press kit) "with the sole purpose of racing in mind." Make no mistake -- the ZX-10R is track-biased and has no pretensions of being the all-arounder the old ZX-9R was.
The compact accommodations, tight geometry and light weight (375 pounds dry, claimed) make the 10R a breeze to throw around at speed, especially through quick side-to-side transitions (of which Homestead has several). With the front wheel right under your chin, the chassis seems wired directly to your brainstem, making for a confidence that only grows as your speed increases. Run it in deep, turn it in late, pick it up at the apex -- whatever you ask from it, the light, quick-steering Kawi responds without resistance.
Instant gratification comes at the cost of some stability, however. It takes very little input to turn the bike, so if you're not smooth and assertive at the controls, the 10R can feel a touch nervous and get ahead of you quickly. It's not quite experts only, but it is less forgiving than, say, the latest GSX-R1000 or (from what Boehm says) the non-twitchy, bedrock-stable CBR1000RR. The 10R's lack of a steering damper doesn't help; the front wheel goes light on command, and it's pretty easy to get the front end shakin', especially over bumpy spots, such as the gutter separating Homestead's infield corners from the banked straightaways of its oval.
Compliance and response from the inverted 43mm fork and gas-charged rear shock were consistently solid. Increasing rebound settings slightly over standard at both ends settled the chassis over hard hits without adversely affecting compliance in the slower, car-scarred corners. Top-out springs on the fork and shock further regulate suspension action, most notably reducing front-end dive under heavy braking. That's a good thing because the front brakes -- radially mounted four-piston Tokico calipers grabbing 300mm "petal-cut" rotors -- are phenomenal, offering excellent initial bite and solid, fade-free performance, even after repeated haul-downs from 140-plus mph for the first-gear hairpin at the end of Homestead's midstraight.
Another difficult-to-criticize component was the excellent "slipper" clutch. Action was light and smooth at the lever, and the back-torque limiter effortlessly ate up gobs of revs -- as many as 3000 at a time -- without a bit of hop at the rear wheel. Unfortunately, this excellent clutch is paired with one of the worst Japanese transmissions in recent memory. Shifting was surprisingly clunky, and missed shifts, especially near redline in the third to fourth transition, were common. Kawasaki is aware of this and actually swapped shift rods halfway through our first day of testing to stiffen the linkage, but the change made virtually no difference. Hopefully engineers will smooth things out before production begins in mid-January. If not, they've got themselves a whopper of a problem.
Team Green has put every bit of its engineering energy into the new ZX-10R -- more, perhaps, than any model since that first Ninja back in '84. Whether or not this ZX-10R will have the same impact on the category as its forefather remains to be seen -- competition is significantly more serious than 20 years ago, with the class-killer GSX-R and such all-new animals as the Yamaha YZF-R1 and Honda CBR1000RR now in the mix. Ridden alone without the benefit of direct comparison, the newest Ninja impressed with its impossibly small stature, rev-happy monster of a motor and fast, flickable on-track manners. After spending the last few years on the sidelines, Kawasaki brings us a literbike that could be king. Good times, indeed.
SECOND OPINION
With no competitors alongside, it's always difficult to judge a new sportbike's power and acceleration at a press intro. But after only a lap or so at Homestead, it was obvious the new ZX-10R has some serious steam. My butt dyno says the 10R has a tad less midrange than the GSX-R1000, but its top-end is easily on par -- if not a bit better.
And it doesn't stop there. The Kawi felt lighter than the GSX-R when flicking through the tight stuff, steering was easier and sharper, and the brakes were fantastic. Even the suspension seemed to lack the typical over-abundance of high-speed compression damping endemic to Kawasakis. It's clear: Despite some niggling details (shifting), which will likely be fixed by production, Kawasaki is back, and the ZX-10R shows it's damn serious.
-- Kent Kunitsugu, Editor, Sport Rider MagazineSport Rider Magazine