An All-New ZX-10R (With Traction Control?), Beefed Up ZX-14 And Revised Ninja 250R Head The List For Kawasaki
Bike
Per the now-usual modus operandi of upgrading sportbike models every two years by the Japanese manufacturers, Kawasaki has revamped the ZX-10R substantially from its last '06 iteration, instilling a host of modifications aimed at re-establishing Team Green's prominence in the literbike class. The aggressive-looking new 10R appears to be a no-holds-barred design with numerous changes drafted in straight from the firm's Superbike and MotoGP racing efforts, with even more of a track focus than ever before.
The 10R wasn't the only big Kawasaki that was entering its two-year development phase, however. KHI engineers surely caught wind of Suzuki's new Hayabusa that is scheduled to be unveiled for '08, and couldn't let Kawasaki's flagship sportbike sit idly by and get one-upped by its main rival. A surprising boost in the 14's overall power (as if it actually needed it...) was accomplished via some subtle changes.
Even Team Green's little Ninja 250R wasn't left out of the upgrade parade. A number of changes to Kawasaki's original entry-level Ninja have taken it a step closer in looks and performance to its high-performance brethren.
ZX-10R
Like last year's ZX-6R, Kawasaki engineers employed the services of a top-flight racer to help with machine development. In the new ZX-10R's case, it was former World Superbike and MotoGP contender Akira Yanagawa, who still competes in the All-Japan Superbike Championship (in fact, at press time, he was a close second in the title chase with two rounds to go).
Because Kawasaki engineers wanted to keep the previous model's superb midrange power intact, bore and stroke remain the same with the all-new engine. A one-piece upper crank- case and cylinder casting shaves more than two pounds of weight and increases overall case rigidity, and the clutch and transmission shafts retain the stacked configuration to cut overall engine length front-to-back. Additional weight was saved by oil channels cast into the cases (replacing external oil lines), and specially designed internal fins in the liquid-cooled oil cooler improve its heat dissipation capacity. The oil pump gear ratio has been refined along with the aforementioned lubrication system changes to reduce drag and improve efficiency.
The crankshaft is all-new, and even though the overall assembly weighs about two pounds less than the previous unit, it still maintains the same inertial force. A new water pump using the same style impeller as the ZX-14 improves coolant flow with less friction, and a new-generation radiator with more tightly packed cores cuts weight and improves cooling.
Up top, the cylinder head features reshaped intake and exhaust ports (the exhaust ports are narrower in the midsection), as well as a redesigned combustion chamber for improved flow and combustion efficiency; compression ratio remains the same at 12.7:1. The exhaust valves themselves have shrunk slightly, from 25.5mm down to 24.5mm. Camshafts are more aggressive, with higher lift for better top-end power.
Induction is now handled by throttle bodies with an oval cross section (velocity stacks are oval as well), and two injectors per cylinder are now used for better overall response. The compact flat-style fuel pump from the '07 ZX-6R permits the same 4.5-gallon capacity as the previous fuel tank, despite the extra room needed for the new secondary injectors. The ram-air intake was redesigned to reduce intake noise and further improve flow efficiency into the larger airbox, which was also designed with better access and ease of maintenance in mind.
The six-speed transmission now features shorter 1st, 4th and 5th gear ratios, and the rear sprocket gains one tooth to further shorten the overall gearing; this would tend to reinforce the notion that Kawasaki engineers wanted to increase top-end power without sacrificing any of the previous 10R's stout midrange.
It appears that the underseat exhaust styling fad is now fading fast, as the new 10R joins the ranks of sportbikes using an under-engine chamber exhaust. A pre-chamber underneath the engine features a palladium catalyzer that allows the new literbike to pass ultra-strict Euro III emissions standards. A single "orthogonal" shape titanium silencer exits out the right side of the pre-chamber.
Of particular interest to us was the description of the engine's ignition system. The press kit describes the new ECU as having "complex program parameters based on extensive rider testing" that utilize an "advanced ignition management system that curtails sudden spikes in engine speed for improved rider control." This new engine management system monitors engine rpm, throttle position, gear position and "vehicle speed" most likely based on rear-wheel speed as measured at the countershaft sprocket. Is this a form of traction control or the basic foundation for one? Kawasaki U.S.A. reps were understandably mum on the subject when we inquired, so a more in-depth analysis will have to wait until we can talk to KHI engineers.