Kawasaki Z 1000J



Make Model

Kawasaki Z 1000J




Four stroke, transverse four cylinder, DOHC, 2 Valve per cylinder.


998 cc / 60.9 cu-in
Bore x Stroke 69.4 x 66 mm
Cooling System Air cooled
Compression Ratio 9.2:1


4x 34mm Mikuni BS34  carburetors


Spark Plug Spark Plugs: NGK B8ES or ND W24ES-U
Starting Electric

Max Power

102 hp / 76 kW @ 8500 rpm

Max Torque

9.3 kgf-m / 67 lb-ft @ 7000 rpm


5 Speed 
Final Drive Chain,  630 endless with 92 links, sprockets 15 front, 41 rear

Front Suspension

Telescopic forks, coil air spring

Rear Suspension

Swinging arm with dual dampers 7-way spring preload.

Front Brakes

2x 236mm discs 1 piston calipers

Rear Brakes

Single 236mm disc 1 piston caliper

Front Tyre

3.25 V19

Rear Tyre

4.25 V18

Dry Weight

230 kg / 507 lbs
Wet Weight 254 kg / 557.8 lbs

Fuel Capacity 

21.4 Litres / 5.5 US gal

Consumption Average

41 mpg

Standing ¼ Mile  

12.1 sec / 112.5 mph

Top Speed

210.8 km/h / 131 mph

Road Test

Cycle 1981

And now for an important message to all Z-1 freaks: You can come home again.

Sooner or later, everyone hungers for a Z-1. Even me. I think it's a phase you go through, like wanting a new bicycle, craving pizza or lusting alter the ash blonde giri in geometry class. Something about the way t he double overhead cams of Kawasaki's venerable inline tour bang open their assigned valves has always set my blood to boiling. To me, the motor has the rhythmic downbeat of a steel foundry. And so, when I finally managed to get my hands on a Z I several years ago. I was re ally primed tor action, just as we all are upon confronting a legend for the first time.

Like the copywriters say, riding a Z-1 lor the first time is like losing your virginity, going into combat and tasting your first beer all in about seven seconds. Nothing can match the surge ol adolescent satisfaction you get from putting the motor on true-blue guys on Honda 7.50s and badass rednecks in '57 Chevies.

Hut alter a while. I realized that riding around on a Z-1 gets to be like belonging to the Marines. Sure, you inspire a certain amount of Tear and loathing in the average civilian wimp, but you also realize that no body but a profootball defensive tackle hopped up on steroids stands much chance of surviving the experience, -lust one soul chilling wobble in a fast corner, the bike weaving around like a scorpion in a death dance, was enough to deflate my enthusiasm for twisty roads. And getting hammered on the turnpike by the still legged suspension wasn't much fun either. So 1 chalked up the Z-l experience as part of my dues as a motorcyclist and moved on to more refined two-wheelers.

That's why, if you're like me, you'll bt glad to learn that it's time to return to your roots. The Z-l is back. It's improved somewhat over the past two years, but now it's ready to sit at the head of the literbike class. Eight years of fine tuning at Akashi have chiseled away the Z-l's rustic tendencies, and what's left is a plain-spoken motorcycle that doesn't flinch at freeways or backroads. It also doesn't flinch at the quarter-mile. Kawasaki now claims that there are 102 ponies locked inside the Z-l motor. It sounds like it. The hollow bark from the twin exhausts will raise the hair on the back of your neck.

There's nothing flashy about the new KZ1000J (never mind the KZ stuff, we know it's the Z-l). It's supposed to be Kawasaki's bread-and-butter hyperbike. The styling is less aggressive. It weighs 37 pounds less. And when you unravel the '81 Z-l's secrets, you find the same dogged allegiance to fundamental verities that produced the stunning KZ750 and KZ550. Simplicity, light weight and the right kind of power account for the rejuvenated Z-l. It's a fully realized modern motorcycle instead of a one-dimensional, high-performance freak. There's no brag to this bike. All it does is deliver the street-bike goods in world-class fashion. Riders of GSll00Es and GSl000Es are going to be looking over their shoulders for Z-ls or trying to catch up, as the case may be.

No matter how modern the whole package might be, though, the Z-l legend begins with the engine. The '81 bike is no exception. Kawasaki shrank the KZ1000 engine's bore a half millimeter so the motor would qualify for the FIM endurance roadracing championship, yet factory data reflects a 10 percent horsepower increase although at the price of a four percent less peak torque. When you drop the hammer on this sweetheart of a motorcycle, the quarter-mile marker appears in only 11.6 seconds. A top speed of 130 mph is only moments away. The engine revs so willingly that it invites you to twist the throttle until the cylinder head blows off its locating studs. And when it comes to throttle response, Kawasaki's reed-valve air injection cleans up emissions so thoroughly, it permits the kind of precise car-buretion that makes other EPA-pleasing bikes feel flabby and gutless. Only the need to choke the engine into life all the time will remind you that this is not a pre-1978 non-EPA motorcycle.

Kawasaki coaxes more horsepower from its long-lived four simply by funneling more fuel into the combustion chambers where a higher compression ratio squeezes more goodness from every drop. Lightweight, aluminum, 34mm constant-velocity Mikuni carburetors replace last year's 28mm slide/needle zinc Mikunis as the first part of the horsepower program. Then the inlet and exhaust ports are 2mm larger than before. The intake valve is 1mm larger and the exhaust valve is 2mm larger Valve lift is also increased about 10 percent to further improve breathing. And thanks to the constant-velocity carbs (and leaner jetting), the new Z-l motor's power boost is accompanied by 15 percent better fuel economy

Unlike previous Z-l engines, the 998cc motor churns out power with Mix Master like equanimity. Two dual-density rubber mounts at the front of the engine (first used on the 1980 KZ1000 shaftie) eliminate most of the shake, rattle and roll. At the same time, Kawasaki engineers have pared the flab from the paunchy motor's internals for a smoother-spinning power-plant. The crankshaft flywheels have been put on a five-pound diet (especially the primary-drive-side web extension) and the kickstarter has been deleted. Increasing the diameter of the generator preserves plenty of flywheel effect, but now the crankshaft doesn't threaten to abandon ship when you go after the horsepower on the far side of the tach.

Keeping the ponies corraled inside this revitalized engine requires some strategic strengthening of the package. The larger main bearings introduced on last year's KZ1000 engines are part of this effort. So is the increase in height of the cases in the gearbox area for more rigidity.

Most of the general upgrading takes place in the transmission, however. By increasing the final drive ratio (numerically) and reducing the internal ratios, Kawasaki has retained almost identical overall ratios to 1980. But because the new gears spin faster they have to transmit less torque, which makes them effectively stronger. The gearbox's output shaft also has been strengthened, another plate added to the clutch and the Enuma chain upgraded.

Of course, no one has ever questioned Kawasaki's ability to build plenty of horsepower into its engines. Being able to uncork all that power without getting bucked into the bushes has been another thing, though. And wonderfully enough, the new Z-l whistles into corners with both ends of the bike working in harmony. It strokes up and down on its air-spring fork and shocks with adjustable rebound damping much like a Suzuki. The Bridgestone tires grip the pavement the way a hyperbike's paws should. The steering exhibits the same quickness of previous Z-ls, but now you can use it to change your path to an apex without the bike wriggling in protest.

Once the fork is dialed to 13 psi and the shocks jacked to position No. 4 for both the seven-position preload and five position damping, the Z-l will even attack racetracks without hesitation The crucible of Willow Springs Raceway's Turn Eight, a full bore, top-gear right-hander, failed to uncover any flaws in the J model KZ1000 but for a little rear-end impreci sion. If you deliberately upset this bike it bobbles more than a GS1000, but up until that point the handling is world-class, a fine balance of quick responses and highspeed cornering stability.

General upgrading of the Kawasaki's frame accounts for much of this sure-footedness. The frame is configured almost the same, but only the engine cradle is identical. Everywhere else, the diameter of the frame tubes has been increased while the wall thickness has been reduced, adding strength while reducing weight. Moreover, the steering head the weak point of the previous frame- -has finally been bolstered by comprehensive gusset -ing. Two cross-braces add to the rigidity of the top tubes. Other significant details include tapered-roller steering head bearings, needle bearings in the swingarm pivot, aluminum rather than iron triple clamps and larger diameter fork tubes.

In terms of dimensions, the chassis now has an inch-longer wheelbase, 1.5 degrees more rake and 0.47 inches more trail, slowing the handling somewhat. A slight reduction in front weight distribution due to the 15 pounds trimmed from the engine and the 18 pounds dieted from the chassis (by Kawasaki's count) preserves the light touch to the Z-l's steering, though.

All of these changes would be for naught if the bike proved as painful to live with as previous KZl000s, so Kawasaki concentrated on getting the bike's comfort quotient correct. The result is the most comfortable Kawasaki I've ever ridden. Basically, the bike smothers bumps because the suspension is very soft. With the fork set to seven psi and the shocks at No. 1 on preload and damping, the Z-l pitches on the Interstate and squats noticeably on acceleration. Still, even though the shocks occasionally bottom out across large bumps, Kawasaki should be congratulated for calibrating a suspension for one-up riding instead of making you live with a bike set up for 500KZ pound loads as usual. The suspension's responsiveness to small inputs is heightened by a reduction in unsprung weight, fore and aft, thanks to a decrease in brake rotor diameter and caliper weight (though at the cost of a slightly spongy brake feel). The fork also carries two anti-stiction bushings in the current fashion, one at the top of the slider, the other at the bottom of the fork tube.

The riding position and all its components show the same appreciation for rider comfort. The attractive seat has dual-density foam to insulate you from road harshness but its softness tends to lock you into one position. The low handlebar lets you lean forward slightly into the wind, and a barback at the triple clamp insures you won't have to lean far. The electrically powered instruments have luminescent numerals and are highly readable. The location of the odometer and tripmeter in the center of the dash lets the speedo be more legible, unfortunately the odometer is slightly tilted away from you so you can't read it. A nice touch is the presence of two turnsignal lights, although the tumsignal switch itself is notchy and clumsy to operate. Meanwhile, the halogen headlight produces a bright beam with a good sharp cutoff. The throttle pull is lighter. The grips are heaven. The shift lever rides in ball bearings to lighten shifting effort, although the action is clunky. Finally, the gas gauge's needle is sufficiently damped to be fairly accurate, and it holds its position when you switch off the ignition.

It's this overall commitment to intelligent detailing that makes the Z-l so impressive. In the past, the big Kawasaki has been something like early Ferraris built to go like a bat out of hell in a straight line and not much else. But this Z-l can take you in any direction on your personal road-map and inspire confidence in your own ability as well as the motorcycle's. Unfortunately, the Z-l runs the risk of being overlooked, since the fuel-injected GPzllOO should siphon off the sporting audience while everyday riders will cling to the KZ1000 LTD. There might not be a place for bread-and-butter bikes in this country any more.

Even so, I've decided that there's got to be a place for a plain-and-simple, no-brag-just-speed motorcycle that gives you your money's worth every time you climb aboard. It's more than a matter of 102 ponies, too. You see, I still get the same adolescent rush every time I fire up this bike's engine, but I'm also pleased that I can ride anywhere at 50 mpg or 130 mph with equal confidence.

The measure of this motorcycle's accomplishment is the fact that it sums up the lessons of the Seventies—comfort, good handling and a good power-to-weight ratio—so we can live with the Z-l's distinctive speed thrills for the Eighties. For a few years, I thought I'd have to give up my Z-l roots for good. Now I don't have to. •