It was only a matter of time before Kawasaki unveiled its answer to the Honda CBR1100XX and Suzuki Hayabusa. The successor to the ZX-11-and continuing a long heritage of Big K roadburners-the ZX-12R has been arguably the most anticipated (and controversial) bike in recent memory.
The most intriguing aspect of the 12R, technically, is its frame. While virtually all Japanese sportbikes follow the same formula of twin (or more) aluminum beams wrapped around their engines, Kawasaki has bucked that particular trend. The ZX-12R sports a monocoque, aluminum frame which joins a cast steering head and cast swingarm pivot (which incorporates the battery case) with pressed plates passing over the top of the engine. The reasons for this are twofold. With no beams splayed around the cylinder block, the motorcycle can be narrower-as slender as the engine, even. And using the portion of the frame which sits atop the engine as an airbox (which, with ram-air pressure as high as it is, needs to be quite sturdy) eliminates the necessity for a separate unit and makes the hassles of getting air through formed beams and into an airbox moot.
Hanging from the ZX's frame is essentially a 1.33-scale ZX-9R engine. Bore and stroke share the same 1.5:1 ratio (same as the 6R also, incidentally), and the 12 shares the 9's general architecture. Where the biggest Ninja engine differs is in the induction department-the 12R is the first fuel-injected Kawasaki sportbike since the old GPz1100, breathing through a quartet of 46mm throttle bodies, each with a four-hole injector.
The ZX-12R's unique monocoque frame incorporates the airbox and battery holder in its backbone. | 
The gas tank flips up, revealing the air filters (1) which slide out for servicing. There are separate access ports (3) for the throttle bodies. |
A stiff aluminum cover (2) acts as a stressed member and hides the battery. | |
As you'd expect, given the Kawasaki's chassis layout, the 12R is a tall, narrow motorcycle. Although the seat is a high 31.9 inches, its narrowness makes the reach to the ground seem shorter. Release the hounds-well, ponies in this case-and you'll hear one of the sweetest stock exhaust notes from the stainless header/titanium muffler (and catalyzer equipped) exhaust system. With a super-close ratio gearbox, pulling away from a stop requires a good dose of clutch slip. And while the cable-operated clutch is light and has a wide engagement, its lack of feel combined with the tall gearing requires a bit of care to avoid a stall in the city. Once underway, drivability in town is good and with speed, the bike loses some of its height and tippiness. Shift into second and a short burst later you're doing 50-miles-per, and the engine is smooth enough you could use only those two cogs around town. Obvious after a few miles is that the bike's crankshaft has been pared to the bone-let off the throttle and you're slowing down now. So use the higher gears, what the heck, the 12R is just as happy trolling along with 2000 revs showing on the tach as 5000. Transmission action is excellent (with or without the clutch) but it's best to come to a stop and use the neutral finder to um...find neutral because it does a good job of hiding if you're moving.
Wind protection at higher speeds is excellent, with the tall screen limiting the windblast to the top of your shoulders. Aside from a few bands of resonance, the Kawasaki's engine is smooth anywhere in the rev range, making it an easy proposition to empty a tank in one sitting-although your wrists will have had about enough by the time the LCD fuel gauge starts flashing at 150 miles. The Zed-Ex begins to show its rough edges when the road gets twisty or bumpy, however. While the suspension is well damped for a moderate pace, pushing too hard over sharp-edged pavement irregularities will give you a worrisome moment, as the high-speed compression damping is quite stiff at both ends. Combined with throttle response that can get downright abrupt over 6500 rpm (and the mill needs to be revved for best results as it is surprisingly peaky), and you'll find yourself backing the pace down a notch on unfamiliar or bumpy roads.
We are far from disappointed with the ZX-12R. It's no slug by any stretch of the imagination, but we would have expected something a bit more, well...polished, for a top-of-the-line motorcycle. The Kawasaki has a charisma that few bikes match, and a lot of people will shell out 12 grand for that alone. Fix some of the rough edges though, and we'd cut to the front of the line.
Back to Big Dogs: 2001 Suzuki Hayabusa and Kawasaki ZX-12R
This story originally appeared in the October 2001 issue of Sport Rider.