Kawasaki hot-rodded the ZX-9R with a number of internal changes to the engine and to the intake and exhaust systems. The lightweight powerplant is last year\'s unit, modified for increased performance, made even more explosive.
The first change is at the intake ducts for the ram air system. This is an increase in the ducts\' size to provide for a higher pressure inside the airbox at high speeds. This, of course, results in an increase in power at speed. The completely redesigned and extended opening of the air intakes is now defined by the bottom of the headlights on top, and by a protruding edge on the bottom that incorporates both ducts into one entryway. This creates a mouth whose lips extend out beyond the rest of the fairing upper, grabbing high-pressure air before it has a chance to pack up or become dirtied by the bike\'s push through the flow.
The ZX-9R\'s CVRD 40 mm downdraft carburetors are an all-new design by Keihin. Their standout feature is the flat intake side of the carb slides, which is intended to offer improved throttle response. The slide return springs on the carbs are also unique in that they are extremely short and do not extend down into the slides as is true of other CV carbs.
On the exhaust side of the engine, the header pipes have been enlarged from the 31.5 mm of last year\'s model to 35.mm, and extended by about two inches between the head and the collector. Kawasaki says that this change is to smooth out the power delivery and give the bike more top end punch.
The intake ports between the carbs and exhaust are now longer and split into dual ports for more of their distance than in the previous version. The intake cam lobe profiles have been modified, as has the cam timing, for an increase in the bike\'s mid-range torque. The camshafts have also been lightened, as have a number of other internal rotating parts, such as the clutch gear.
The result of the modified cam lobes and altered timing is an increase in the engine\'s compression ratio from 11.5:1 to 12.2:1. And the result of this increased compression is that now the ZX-9R requires 90 or higher octane rated gasoline.
The inside diameters of the piston pins have been decreased by a full mm by increasing the pins\' wall thicknesses. This is to ensure that the pack will stay together under the loads of the increased compression.
The ignition sending unit on the crankshaft has been given many more spikes in order to "update the ignition unit more often for more accurate timing," according to Kawasaki. Previously, the sending unit signaled every 90 degrees, but the new one does so every 15 degrees. The ZX-9R now also carries 10 mm twin-electrode plugs fired by a new 16-bit igniter that is smaller and lighter and said to have a faster rise time to keep the plug mounted coils cooler.
The 2000 transmission has been modified, too. The main changes are the back-cutting of third and fourth gears, re-shaped shift grooves in the shift drum, and a longer output shaft that was necessary to move the chain further out for clearance of the wider rear tyre.
Kawasaki ZX-9R Full Test
The ZX-9R\'s frame looks the same but isn\'t. The main outer frame beams are now ten mm taller and the steering head tube has been increased by 12 mm in length. These changes were made to give the bike more rigidity. The rear subframe is now a bolt-on unit rather than being welded in place.
The swingarm was completely redesigned with new extruded aluminum arms that are without internal rubber dampers. Kawasaki tells us that the damping is taken care of by internal ribbing, which makes the swingarm more rigid yet lighter, too. The swingarm\'s pivot shaft diameter has been enlarged by five mm to 25 mm, for added strength, but it is still hollow, again for lighter weight.
Up front, the fork offset has been reduced by five mm, which results in an increase in the bike\'s trail. On the rear, a screw-type ride height adjuster is now located at the top of the shock, just like on the ZX-6R.
The linkage rates have also been changed on the rear suspension\'s Uni-Trak system to make the ratio more linear and less progressive. The beginning of the stroke was softened while the end of the stroke was stiffened from last year\'s ratio, but the early part of the stroke is still softer overall than the end of the stroke. Additionally, the suspension settings on each end of the bike have been changed to improve the ZX-9R\'s setup and handling on the street and the track. Both axles are five mm larger in diameter for, again, increased rigidity.
The Nine\'s front brake rotors have been increased from 296 to 310 mm, and the rear wheel width has been increased by half an inch to six inches with the recommended tire now a 190 rather than a 180. Contrary to popular belief, a wider tire does not result in a bigger contact patch, but only in changing the shape of the tire patch. Unless, of course, less air is put in the tire. What a wider tire does is make the contact patch wider but shorter.
The Nine\'s new headlights are lightweight units with plastic lenses. Low beam and high beam are in both of the twin headlights but, with the key on and the engine not running, only the small, centrally-located parking light above the headlights will illuminate.
The speedo and gauges are thinner, and the analog dials do the groovy full sweep thing when the key is first turned. The speedo gauge also includes an LCD that displays the odometer, tripmeter, and clock. On the tach is an LCD that tells the bike\'s coolant temperature and has an additional warning light. The ZX-9R also features four-way flashers, as has been common on Kawasakis for a couple of years now.
Under the lower triple clamp is a skirt attached to the forks that blocks off what used to be an area of uncontrolled air between the fairing and the steering head. These things are showing up on more and more bikes, so either they actually help with aerodynamics or cooling efficiency, or it is one of those things that engineers do because it\'s just part of engineering culture.
The "Pearl Purplish Black Mica" finish of the ZX-9R that we tested allows the charcoal-colored components to blend into the shape of the bike rather than stand out as bolted-on doodads. But the splashy multi-colored "Lime Green/Metallic Violet Royal" with charcoal doodads is also available.
Kawasaki ZX-9R Full Test
The engine of the ZX-9R is just as expected: the thing freakin\' storms. At almost any rpm, the Nine rips forward at an eye-watering pace that is incredibly seductive. There\'s nothing not to like about this bike\'s power, except maybe for the jump in torque that, in first gear, can surprise first-time riders.
With the new carburetors, the ZX also has a tendency to jump when the rider goes from full off the throttle to back on the gas. This behavior has been noticed on some fuel-injected machines, but this is the first carbureted bike that we\'ve ridden that did it. We removed all slack from the throttle cable so that the point of lurch could be easily predicted, which helped a great deal. With slack in the cable, the rider never knew exactly when the bike would jump back on the power. We should also mention that the bike has an idle that is higher than most. The recommended setting is between 1,050 - 1,150 rpm. It could be possible that, at an even slightly higher setting, the lurch would go away.
On tight roads, the new ZX-9R behaved well but felt surprisingly heavier steering than did the last version of the bike. This is probably attributable to the increased trail and wider rear tire. The bike\'s frame has been slightly lengthened to maintain the same wheelbase from before the reduction in fork offset, and that could possibly contribute to the new feel, too. Also, with larger rotors up front, there is a slight increase in unsprung weight, which could add to the heavier feel. All this is to point out that there\'s never one reason for a bike\'s behavior.
With the feedback of the new bike\'s geometry and suspension, the rider is made to feel more comfortable by finishing all braking before entry into turns to get the bike settled out. So, since the rear ride height is adjustable, we raised the back end by a half inch to see if we\'d like that better. We did. With the raised rear, the bike turned in much nicer and trail braking could now be carried into the turns with comfort. It seemed to connect the rider better with the front end of the bike and allow it to give more feedback.
The bike still is much more of a sportbike than the version of \'97, but our test unit didn\'t have the lightweight feel of the last version of the ZX-9R. Except for the lurch from off throttle, the engine is a hoot, but the chassis probably won\'t feel as easy to ride to most street guys. Yet it could be a whole different story on both the drag strip and the roadracing course. With the refinements to the chassis, there is more to work with for both of those endeavors, and this bike could possibly set some records in 2000.
On most roads in the States, along most rivers, and through most hills, this bike will run with any of them. Out here in SoCal, however, where the turns are all tight and blind, light and quick-steering machines have the edge. The riding position is very comfortable for a sportbike and Kawasaki even added extra padding to the seat.
When the new Nine that this improved version is based on first appeared in \'98, it found itself up against the mighty competition of Yamaha\'s new R1 and a new Honda CBR900RR. It seems as though, with this new version of the ZX-9R, although Kawasaki might not beat those bikes around the corners, they just might beat them down the straight.