Soup Test: 2006 Kawasaki ZX-10R
Team Kawasaki's Super Superbike Platform: dig that velvety smooth powerband
by eric putter
Monday, January 30, 2006

Making big dyno numbers has never been a problem for Kawasaki, but laying down that potential thrust in a predictable, fluid manner is ever more difficult. The new ZX-10R doesn't make more peak horsepower than its predecessor, but the valleys of its former powerband have been filled in with velvety smooth forward momentum.
Roger Lee Hayden brushed past on the binders with inches to spare as we peeled right for turn 12, beginning another run through California Speedway's final infield section. Big brother Tommy lurking within striking distance, I became a Hayden sandwich, just like Jason DiSalvo did many times during last year's AMA Supersport brawls.

"Damn Country Boy," I mumbled as the kid's cartoon-scrawled Arai whizzed past my head. In lockstep, we pointed and shot our way through this first-gear, 9-turn combination, the youngest Hayden boy putting on a Dunlop-spinning, sideways-slithering display of bravado the entire way. In the moment that it took me to eye my flight path and tuck in for a strong launch down the banked front straight, Rog disappeared in the distance. Tommy deftly zigged left in hot pursuit.

This wasn't a battle for early season points. Truth be told, the boys were engaged in PR duty at Kawasaki's U.S. press introduction of the 2006 ZX-10R and they caught me during an initial "out" lap while scrubbing in new tires on a pair of stock bikes. Turns out that Rog was entertaining himself while putting some heat in the skins and Tommy didn't want to risk a sketchy move on yet another wobbling motojournalist in this relatively slow, tight section.

In addition to summoning the MotoPress Corps to California Speedway for a ride on the all-new ZX-10R, Kawasaki enlisted the Hayden boys and Doug Chandler for some fun on a balmy, 60-some-degree So-Cal 'winter' day.
The new bike is a tremendously capable racer chaser, but let's back up a few laps. Like all new-model launches, this one started with a detailed spin and spec session, otherwise known as a marketing overview and tech briefing.

The tastiest bit of spin concerned how Kawi engineers straddled the middle ground for years between Honda's do-it-all-comfortably CBRs and Suzuki's razor-sharp GSX-Rs. Kawasaki's Vice President, Planning and Marketing, Barry Beehler, wowed the crowd by admitting that there was a period during which his company's product-development crew was asleep at the clip-ons.

Once awakened, Kawasaki's corporate sportbike philosophy took a huge U-turn. No longer commissioned to simply produce motorcycles that fulfilled class requirements and had a long floor life, in 2003 Brand K's designers were given free reign to explode the narrow, shallow box in which they were constrained to build class-leading, track-focused machines.

This new creed's success was first seen in the 2004 ZX-6R and RR. Bearing the fruits of a deadly serious "win on Sunday, sell on Monday" philosophy, the 599cc ZX-6RR homologation special has carried Tommy Hayden to the past couple AMA Supersport championships and the 636cc ZX-6R is Kawasaki's best-selling motorcycle.

Duplicating this command performance on both fronts with the 2004-2005 ZX-10R wasn't in the cards. The bike may have won nearly every liter-bike shootout worldwide, but, as the goes, knowing that it wasn't a competitive platform, Team Green didn't make a big push for racetrack glory—hence the factory team didn't prep it for the U.S. Superbike series and a lackluster, B-level effort was undertaken in World Superbike. Another theory is that the AMA's short-range rulemaking and Kawasaki's Yen-draining MotoGP efforts stymied superbike development.

After assessing this constructive—and sometimes destructive—criticism, everyone involved with the 2006 ZX-10R zeroed in on an all-encompassing engineering goal: To make the 10R go faster around racetracks than any other bike.
In an unconventional gush of corporate honesty, it was divulged that the 2004 ZX-10's designers made too many engineering tradeoffs in the name of building the lightest, fastest and baddest sportbike on the planet. Today's assignment: to investigate if they repeated the errors of their ways on the second-generation ZX-10R. If jumping back into the AMA Superbike class after sitting on the sidelines for three years is any indication, the bike must be impressive. Committing Tommy and Roger Lee to the premier class is the biggest story of this pre-race off-season.

Utilizing input from the world's press, customers, as well as various racers and test riders, including the Haydens and their mentor, three-time AMA Superbike champion Doug Chandler, engineers got to work on the 2006 version soon after the 2004 bike was unleashed.

Stressing that the white-coated engineers absorbed each and every message, Kawasaki Sportbike Product Manager Karl Edmondson prefaced major design improvements in his action- and information-packed PowerPoint tech presentation—complete with dramatic music, no less-with "You guys complained about...," as if the assembled journalists were the only ones to take issue with the previous model's bad habits.

Although the previous ZX-10R inevitably won magazine shootouts over the soft, heavy CBR, not-quite-there R1 and outstanding GSX-R, editors complained about the muscular Kawasaki's nervous, flighty nature, lack of a steering damper, crummy transmission and hard-to-read LCD tachometer. Nonetheless, these character-building traits add up to one hell of an exciting ride. On serpentine canyon roads, this raw, untamed land-based missile demands respect, a deft throttle hand and serious gymnastics to keep it going straight with both tires on the tarmac.

Tommy Hayden's track-based needs are a bit more refined. Despite breaking his hand before Laguna Seca, he soldiered on last year to defend his Supersport championship, but quickly relinquished his ZX-10 in Superstock. "The bike was just too hard to ride," he remembered not so fondly in Fontana's pit lane. "This was our worst track on that bike. Broken hand or not, the engine just hit too violently and the Suzukis and Yamahas were much better in the transitions."

Chandler, who did a great deal of late-development testing on the 2006 model and was on hand for its U.S. press launch, more succinctly cited the 2005 version's transmission issues, fading brakes, lack of stability under braking and the chassis' incompatibility with a quick-steering "short (wheelbase) setup" due to its nervous habits.

After assessing this constructive—and sometimes destructive—criticism, everyone involved with the 2006 ZX-10R zeroed in on an all-encompassing engineering goal: To make the 10R go faster around racetracks than any other bike. Marketing types conceded that a very small percentage of Ninja buyers ride on racetracks, but, nonetheless, every one of them wants to buy the bike that posts the quickest lap times-or boasts the biggest dyno numbers, lowest quarter-mile time, highest top speed and lightest weight-whether or not they can wield the resulting performance.

Racer Support

After denying the rumor that a ZX-10RR homologation-special is in the works, Kawasaki announced a 30-percent increase in racing kit parts for the 2006 10R compared to last year's model—115 so far, from adjustable ECUs to wiring harnesses. Team K has also bolstered its commitment to the ZX-10R's racetrack success. A creative, 100-bike dealer sponsorship program was initiated and nearly two million bucks in racing contingency money put up for grabs.

Based on the long-running and hugely successful Team Green racer support program, the new Dealer Assist Race Program makes available a combined mix of 100 ZX6s and 10s that come with a parts allowance and a complete sponsorship package.

Kawasaki's roadracing contingency coffers just got richer, wider and deeper, too. There's $1,788,275 available in the pot, or 28 percent of Kawasaki's total payout for all disciplines—from drag racing to Supercross. In AMA Superbike, for example, the floodgates open up to the tune of $7000 for a win. A 20th-place lapper gets $100 hazardous-duty pay. Supersport and Superstock racers who climb to the top of the box will earn $1000; a Kawasaki-mounted racer at the bottom of the top-10 takes home 100 bucks.

Brewing a class-leading elixir of 164 rear-wheel horsepower and 80 lb.-ft. of torque, the 2005 ZX-10 wasn't in grave danger of being left far behind. So, rather than simply injecting yet more chassis-upsetting peak power, Kawasaki's mission was accomplished by smoothing out power pulses over the entire rev range, juggling some frame specifications and equipping the new bike with a steering damper. In theory, this would allow it to get in and out of corners quicker—where most races are won and lost.

To do so, the 2006 iteration has 206 new and improved items: 90 in the engine bay and 116 others sprinkled throughout like pixie dust to magically transform it from an over-achieving, dragon-slayer into an over-achieving, yet kinder, gentler beast. Here are the bike's major, personality-transforming highlights.

Starting at the 998cc powerplant's core, a new crankshaft with increased flywheel mass allows the motor to rev in a more linear fashion, improving off-corner acceleration and taming the bike's predilection to wheelie under hard acceleration in the lower gears. Contributing to this more linear powerband are ultra-fine-atomizing injectors that spray even smaller, 50-micron droplets (they were a huge 70 microns last time around) into reshaped inlet tracts, remapped ECU and more progressive throttle pulley. This final detail item puts an exclamation point on Kawasaki's pinpoint focus to achieve its goals.

To gain back some of what was lost in softening the ZX-10's hit, the intake system was totally revamped to more efficiently fill the cylinders. A bigger ram-air duct and modified airbox route fresh air. A pair of dual-valve, 43mm throttle bodies are new. The injectors were re-angled and moved closer to the stainless-steel intake valves, which have shrunk (31mm vs. 30mm) in the name of aiding intake velocity.

Transferring all of this free-revving power to the ground is an updated transmission. To smooth gear changes internally, all of the tranny's splines are barrel ground to remove burrs and other defects. Externally, a stouter-looking shifter and linkage complement this metallurgic massaging. The 10's slipper clutch is back with a lighter "jutter" spring to better keep the rear wheel hooked up during rapid-fire downshifting and heavy braking when setting up for corners.

Too much power? Wheelies everywhere? Not one of the press corps' power-drunk, wheelie-inclined hooligans ever broke motojournalism's golden rule when testing the former ZX-10R: In the wild world of editorial hyperbole, there's no such thing as horsepower overload or a bike that carries its front wheel too often.
And what about those dual mufflers bulging out from both sides of the tailpiece? Kawi's marketers requested something with more in line with the ZX-RR's MotoGP look, but the side-exit option was nixed because it wouldn't provide the desired can volume. An under-tail muffler was deemed sooo 2004. Besides, this latter arrangement suffers from unnecessary complexity, added weight and decreased performance. Apparently, the titanium, dual-Bazooka setup with integrated exhaust valve was the best compromise. It incorporates a pair of catalyzers in a stainless-steel section that allow the engine to meet super-stringent 2007 European emission regulations.

Further exploiting the motor's new demeanor, it was repositioned in the chassis to continue the faster-lap-time-is-job-one theme. First off, the engine was raised in the frame to move the crankshaft 20mm higher for quicker roll response from one extreme lean angle to another, then the cylinder bank was tilted up 3 degrees (from 20 to 23 degrees) for improved mass centralization.

Chassis-only moves began with relaxing the front-end geometry by moving the steering head 15mm forward, increasing caster and shifting the weight balance rearward. The aluminum frame structure is unchanged, but incorporates more rigid top motor mounts. The redesigned cast aluminum rear subframe is removable. A new and very trick-looking swingarm is massively braced at the bottom and engineered to be super-stiff torsionally, but offer nominal lateral flex. Rounding out the chassis adjustments, the arm's pivot point was lowered by 4mm to aid rear-wheel traction.

Other than that beautifully sculpted swingarm, the biggest visual clue to the 10's handling upgrades sits conspicuously atop the triple clamp. Not only did Kawasaki fit a much-requested steering damper, it went with a very high-profile Ohlins unit. This isn't some lawyer-mandated throwaway hidden below the steering stem; it's a top-shelf, dual-chamber, 18-way-adjustable stick-type (rather than rotary) unit. In light of the aforementioned changes that theoretically foster chassis stability, why the engineering about-face? The official line was a simple one: This wasn't an engineering decision at all; it was a marketing call—apparently against the white coats' wishes, no less. Man, those guys in green really are listening and fighting for us.

Guess someone forgot to remind them to offer all of these killer upgrades but not to raise the bike's weight or price for 2006. The ZX-10R gained 11 pounds in its transformation and now retails a measly $200 bucks higher, at $11,199-well within the current open-class ballpark. Heck, that sweet steering damper alone could cost twice the price increase. Besides, Tommy and Roger Lee Hayden could have spent all of their retirement funds (and even their MotoGP hotshot brother Nicky's) on the extensive re-engineering that their Superbike platform received in the off-season.

Extrapolating approximate 2006 open-class wet weights using Motorcyclist magazine's "Hard Numbers" and updated new-model information for guidance, the porkier, 444-lb. ZX-10R is a pound heavier than the GSX-R, but still 5 lbs. and 7 lbs. lighter than the new-and-improved CBR-RR and slightly revised R1, respectively. Thankfully, the new 10's weight is hidden well at speed.

Getting up to speed is what the 2006 ZX-10R's press launch was about. This introduction was not limited to a four-lap MotoGP journo ride o' terror on a strange track in a foreign land. It was a more low-key, close-to-home event where journalists rotated through a series of 15- to 25-minute stints on California Speedway's national course, the very same track Mladin and company will tear up in April.

According to the bike's lap timer, my six sessions added up to 111 minutes in the saddle, enough for nearly 80 go-rounds on the 2.3-mile circuit, a grand total of 184 miles. This closed-course evaluation was backed up by 300 street miles on 2005 ZX-10Rs, days before the intro and immediately post-test.

Folding my arms and legs around its curves during our first embrace, the Tenner felt smaller but not heavier; its cockpit a little bit tighter, offering a more intimate sit-in-it vibe, rather than a less connected sit-on-top feel. The redesigned fairing and scalloped fuel tank allowed this 5'6" tester to quickly get into a wind-cheating tuck and keep his hands out of the breeze, even while approaching 165 mph on Fontana's front straight.

Buy The Numbers: Putting Things In Perspective

Numbers culled from Kawasaki on the day of the press intro
Tom/Rog on Superbike, January 18, 2006: 1:26s
Tom/Rog on 2006 ZX-10R stocker, January 19, 2006: high 1:31s

2005 Fontana US Superbike Round Data
Mladin's track record-tallying qualifying performance: 1:23.61
DiSalvo's 1000SS pole: 1:24.68. (This would have put him 4th on the SB grid).
Tommy's 1000SS qualifying time: 1:25.92. (This would have put him 7th on the SB grid).
Tommy's 600SS qualifying time: 1:26.67

Turning a wheel at Fontana for the first time, I spent the first session in reconnaissance mode learning which way the 21-turn course bobbed and weaved, searching for braking markers and surveying the pavement. With just 18 minutes in the saddle, it was quickly apparent that the new ZX-10 was a friendlier, more competent motorcycle which shifted better, accelerated without drama and threaded a set of twisties effortlessly. Also that its yellow-beamed shift light—set at 11,000 rpm, according to the much-improved tachometer-and the checkered flag came on much too soon.

As the track melted into the background with familiarity, the ZX-10R's potential came into finer focus. Progressively, throughout the day, speed increased, braking points deepened and steering inputs sharpened as the goal of comfortably laying down fast laps to better test the tackle replaced street-riding sensibilities.

The 10's engine motivated these sorties with velvety smooth off-corner acceleration and ultra-linear delivery. There are no distractions in its powerband to dampen focus on the next obstacle as the bike lunges ahead with true open-class authority starting at 7000 rpm. Even in Fontana's long, tricky, double-apex Turn 5-6 section, the no-drama motor's great throttle response and lack of driveline lash allowed the machine to track straight and true.

Many tight portions of California Speedway were ridden in the 10's tall first gear, which carries it to around 110 mph. This gave hundreds of opportunities to make the motor sing at all octaves—from a honking basso profundo in the sub-basement to a falsetto as it climbed to a towering 13,000 rpm redline, 500 rpm higher than the last-generation motor revved. In any cog, whether charging down short chutes from corner to corner or maximizing acceleration on the banking, the new engine picked up revs noticeably quicker and more transparently because the dips and rises in its predecessor's torque curve were massaged out.

All that and not one missed shift. The newly massaged transmission and shift mechanism mesh in perfect harmony. Gear-change action is positive, with none of the former model's notchy feel. The tranny doesn't mind quick, clutch-less upshifts and the slipper clutch works seamlessly. A few purposely ham-fisted corner-entries didn't elicit rear-wheel lockup or so much as a good chirp.

After the Rog-n-Tommy incident, you'll be happy to know we don't offer a podcast of Putter's screams.
Along with the stronger, yet more relaxed motor is a world-class chassis that further puts the mind at ease when wielding the sharp end of a 160-horsepower go stick—whether chasing the Tail of the Dragon around Deal's Gap or dealing with a five-second gap while chasing a bitter rival with three laps to go at Laguna Seca. Coming down from speed, braking stability is excellent and the new-age, direct-action radial-pump master cylinder offers incredible feel and produces lots of progressive power with little effort.

The ZX-10's re-jiggered dimensions give the bike a light feel that belie its extra weight. With this new mass centralized, it didn't balk at California Speedway's flip-flop chicanes. Where the 2005 version required firm countersteering when demanding that it change direction rapidly or hold a particular line, on this latest iteration quick transitions and mid-corner corrections are accomplished without breaking a sweat.

Further setting this new Ninja apart from its predecessor, the '06 pounds from corner to corner in first and second gears without raising its front tire and shaking its head as redline approaches. That's not to say it won't wheelie on command or get a little lightheaded in challenging conditions.

That's just what happened when the stock Dunlop Qualifier street tires were swapped for sticky Dunlop Sportmax GPs. Unfortunately, they brought out one of the old ZX-10's bad habits that didn't appear with the 2006's original-equipment tires. Traversing a section where we purposely cut the track, accelerating through some bumps near the top of first gear at 100 mph or short-shifted into second, the bike gently shook its steering head in protest. This process was repeated lap after lap when accelerating over a particularly rough pavement transition before shooting up the front straight's banking.

More important than the expensive hotels and snazzy restaurants motojournalists endure on press junkets, the greatest luxury is having factory technicians at one's disposal to undertake such tasks as faceshield cleaning after each session, ego-boosting moral support and complete bike setup.
These are the stock and track-day baseline settings that Kawasaki's Technical Services department used to set up all of the ZX-10R press bikes at California Speedway.
PRELOAD17mm (7 lines showing)15mm (6 lines showing)
RIDE HEIGHTAs deliveredAs delivered
COMPRESSION10 clicks out from full stiff6 clicks out from full stiff
REBOUND10 clicks out from full stiff8 clicks out from full stiff
PRELOADAs delivered180mm unloaded
RIDE HEIGHT6mm spacer1mm spacer
COMPRESSION4 turns out from full stiff4 turns out from full stiff
REBOUND2 turns out from full stiff1-3/4 turns out from full stiff
These are the stock- and race-compound tires and their respective air-pressure specs that Dunlop technicians from Sport Tire Services ran on all of the ZX-10R press bikes at California Speedway.
Dunlop Qualifier
Front:120/70x17; 30 psi
Rear:190/55x17; 30 psi
Dunlop Sportmax GP
Front:120/70x17; 31 psi
Rear:190/50x17; 29 psi
The culprit: Dunlop's latest-generation high-end rubber that doesn't yet come in the 10's new-spec 190/55 rear tire size. As a workaround, we had to make do with the 4-1/2mm taller (from axle to ground) 190/50 Sportmax GP. This increased tire height, which was exacerbated by their growth when heated, steepened the bike's rake, naturally making it less stable over bumps at high speed.

Having tuned out as much of this effect as possible during the previous day's testing, Kawasaki's Tech Services folks offered up a few clicks of the steering damper. Going three positions stiffer calmed the front end with little difference in steering effort.

In every other situation at Cal Speedway, the fully adjustable suspension package—featuring the same 43mm inverted fork and piggyback shock-which were set up softer than the previous model or any recent Kawasaki sportbike—sucked up bumps rather than transmitting them through the frame to the nut behind the handlebars, allowing riders pick up the throttle earlier. Again, all in the pursuit of faster lap times.

In less than 200 miles of testing, it was easy to see that the 2006 ZX-10R has more of everything racers and highly skilled street riders need: prodigious torque and smooth power to pull cleanly out of corners, sharp handling to effortlessly knife through tricky combinations, uncompromised stability and incredible brakes wrapped up in a handsome, well thought-out, hospitable package. The previously mentioned tire-induced headshake and the big Kawi's slight resistance to turn-in under trail braking were the only chinks found in the ZX-10's stately armor.

We'll know soon if the second-generation ZX-10R accomplishes job one. It certainly was the fastest bike around Kawasaki's Autopolis test track during its maiden voyage with Tommy and Roger Lee manning the clip ons. Within 10 laps of comparing the team's well-developed 2005 ZX-10 Superstock bike to an identically set up 2006 version, the boys consistently lapped one to two seconds faster on new machine.

These first dates were wildly successful. As it turns out, product manager Edmondson wasn't blowing smoke. Kawasaki really is focused, committed and determined to heed customer demands, cater to racers' needs and follow through with solid after-sale support, producing sportbikes that exceed expectations.

The 2006 ZX-10R certainly does.

Eric Putter is a 20-year veteran motojournalist with editorial credits ranging from Cycle World to Wired magazines.


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