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Sportbike Overview
1998 KAWASAKI NINJAŽ ZX-9R:
Redefining Big-Bore Supersport Performance!

There's a new Kawasaki NINJA in town set to redefine the word performance in a big-bore supersport motorcycle. The all-new NINJA ZX-9R is claimed to combine awesome power that eclipses that of most other open-class motorcycles with a lightweight chassis that provides the nimbleness of a middleweight supersport machine.

Packing some the most sophisticated engine technology into its all-new, compact and lightweight 899cc engine, this new 900 looks to challenge its larger NINJA ZX-11 sibling for the distinction of being one of the quickest production motorcycles in the 1/4 mile.

It's sure to handle the twisties, too, with an all-new short-wheelbase chassis design based on feedback from Kawasaki's factory superbike racing machines. A redesigned UNI-TRAKŽ rear suspension system with extruded aluminum swingarrn helps bring the ZX-9R's dry weight down to 403.5 pounds. It even looks svelte in sleek new bodywork that not only provides improved aerodynamics but a fresh new look to the NINJA line.

The new fairing only partially hides the powerful, liquid-cooled engine that is nearly 20 pounds lighter than the previous ZX-9R powerplant. To get significantly more power across the rev range, and especially at high rpm, the bore was increased 2mm and the stroke decreased. Enlarging the bore allowed both the intake and exhaust valves to be increased 1 mm in diameter to 30 and 26mm, respectively, for increased efficiency and power. The valves are now directly actuated by the dual overhead camshafts for reduced friction and weight plus improved high-rpm valve control. Narrower valve angles, 12 degrees on the intake and 13 degrees for the exhaust, allow for a flat and highly efficient combustion chamber.

Kawasaki's Twin Ram Air induction system draws fresh, cool air from ducts at the front of the fairing to pressurize the airbox as speeds rise for increased power. The quartet of Keihin CVKD 40mm carburetors feature the new Kawasaki Throttle Response Ignition Control (K-TRIC) throttle position sensor. Linked to the ignition system, K-TRIC adjusts ignition timing for all throttle settings. The ignition system also uses compact, spark-plug mounted ignition coils, similar to those used on Formula 1 car engines, to save weight and keep spark plug voltage consistent.

The alternator was moved from behind the cylinders to the end of the new lightweight crankshaft. Rare-earth magnets are used to reduce flywheel weight by over one pound, minimizing the alternator's effect on the crank at high rpm yet producing the same output.

Engine weight and dimensions were further reduced by following the design of the incredibly compact and powerful NINJA ZX-6R engine. The outer diameter of each transmission gear was reduced and its width increased for added strength, while the distance between the input and output shafts is reduced and now matches that of the ZX-6R. The new compact clutch has plates the same size as those in the ZX-6R, with an additional plate added over the number found in the ZX-6R clutch, and is cable actuated for reduced weight and simplicity.

More pounds were shaved through the use of recyclable magnesium cam, clutch, generator, pulser and chain covers. A brushed titanium muffler caps the four-into-one titanium exhaust system, except for the California catalyzer-equipped versions which have a stainless steel muffler with integrated catalyzer.

While the engine added muscle and dropped some weight, the chassis also went on a diet. The twin-spar aluminum frame now fully uses the engine as a stressed member, eliminating twin front downtubes and their weight. The wheelbase was shortened 25mm for responsive handling.

A redesigned extruded aluminum swingarm sheds more weight yet remains exceptionally rigid. Kawasaki's exclusive UNI-TRAKŽ suspension linkage system applies progressively stiffer spring and damping rates as the suspension is compressed to the rear shock, which comes from the ZX-7R. The piggyback-reservoir, nitrogen-charged shock has a special bladder separating the nitrogen from the hydraulic fluid instead of a floating piston for increased fade resistance.

Up front a new conventional cartridge fork is utilized for optimum weight savings while retaining rigidity for superior handling. Aluminum triple clamps securely hold the 46mm tubes in place. The front brakes feature light 296mm discs to reduce unsprung weight. Clamped by powerful six-piston calipers, the front discs and 220mm rear rotor provide all the braking force needed to rapidly stop this lightweight machine.

When designing the new bodywork, Kawasaki engineers tried to save weight wherever possible. The free-form projector headlight set in the compact, racing-style fairing is extremely lightweight. An electronic speedometer / odometer are driven by sensors located on the countershaft sprocket nut. The mirrors and turn signals are designed to be small and lightweight, and nylon bungee straps are attached to the rear of the seat to eliminate frame tabs and protect the finish of the new slim seat cowl.

While the new look of this NINJA motorcycle is obvious, the improved seating position and comfort will only reveal themselves when the ZX-9R is ridden. With the awesome power of the new engine and superb handling from the new chassis, the Kawasaki NINJA ZX-9R will also reveal its superiority in the big-bore supersport class.

1998 NINJA ZX-9R FEATURES:
ˇ All-new lightweight engine
ˇ Direct actuation valve train
ˇ Twin Ram Air induction system
ˇ Alternator moved from behind cylinders to end of crankshaft
ˇ Rare-earth alternator magnets
ˇ K-TRIC throttle position sensor linked to ignition system
ˇ Curved surface, large-area radiator
ˇ Compact, stick-type spark plug mounted ignition coils
ˇ 4-into-1 exhaust with titanium muffler (stainless steel muffler on California models)
ˇ Magnesium engine covers
ˇ Lightweight aluminum perimeter frame
ˇ Adjustable 46mm cartridge fork
ˇ Bottom-Link UNI-TRAKŽ rear suspension system with adjustable rear shock
ˇ 6-piston caliper front brakes
ˇ LCD clock, odometer, trip meter and bar-type temperature gauge
ˇ Sleek new bodywork
ˇ Easy access to oil filter and drain plug

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