Kawasaki GPz 1100 / Z 1100GP

The Kawasaki GPz1100 B1 and B2 are motorcycles that were manufactured by Kawasaki in 1981 and 1982 respectively. Both models featured a four-cylinder, two-valve air-cooled engine design with a capacity of 1,089 cc producing 108 bhp (81 kW) in the B1 and 109 bhp (81 kW) in the B2.[1] This engine was an evolution of the powerplant used in the previous Kz1000 series, itself descended from the Z1. In 1983 the GPz1100 was completely revamped in both cosmetic styling, suspension and updated engine. The model number changed to ZX1100A1.

Curses on the inventor of the bread box. When that otherwise useful appliance arrived it became a benchmark. Things were bigger/smaller than a breadbox. From there we evolved into evaluating from the standpoint of something else, as in faster than speeding bullets, busier than hogs on ice, etc.

Getting nearer to our subject, motorcycle testing has veered toward overdoing this. When a particular machine arrives it saves time and creative energy if the headline writers can say BIGGEST!

FASTEST! while the fine print talks about more comfort than model X, lower seat than model Y, less buzz at the grips than model Z. Not a bad thing; the reader probably hasn't ridden, say, the YZ490, but if he's been on an Ossa Pioneer or Suzuki TM 125. it will mean something to be told the YZ490 is faster than both of them put together.

Except that in the present case we have here the Kawasaki GPzllOO. Heavy Metal. Kawasaki's own distinct brand of technology, a linear and spiritual descendant of the raucous ol' Z-l. It isn't the most expensive motorcycle on the market, nor the most complicated, or most distinctive, most comfy, most demanding, etc. Kawasaki thinks the GPzl 1 is the quickest and fastest production-bike on the market but at this writing there are slightly quicker rivals and anyway, to swoon over fractions of a second in the quarter mile, or to quibble over esthetic appeal of round vs angular vs wedge fuel tanks is to miss the important part.

The GPzl 100 is all Kawasaki and it works.

This is the result of three converging lines. First, the Z-l that picked up Kawasaki's performance image as created by the two-stroke Triples, raised Honda by 150cc and set the big K in stone as the hot rod. Second, Kawasaki's engineering theme of simplifying and adding lightness, as seen with the KZ650, the KZ550 and KZ750. Third, sports bikes, while others were expanding on the softcore chopper theme.

The Z-l of course grew into the KZ1000 and went (with success) super-bike racing but the other factories matched and beat Kawasaki in the various published tests. They had more power and speed. So early last year Kawasaki introduced the GPzl 100, derived from the KZ1000.

Major modifications were involved. The 1100 is the basic crossframe Four, two cams, two valves per cylinder. Compared with the KZ1000, the 1100 got a larger bore, a lighter crankshaft, revised valve timing, more valve lift, higher compression ratio and bigger valves, all of which is standard hot rod stuff. The GPz also got electronic fuel injection, which is big buck high tech not-quite hot rod stuff.

One can't call these ideas gimmicks but the various factories do seize various engineering themes, like maybe tur-bocharging or water-cooling or single shock rear suspension or anti-dive forks and emphasize them. Sometimes several factories start down the same path at nearly the same time.

Kawasaki's pet, so to speak, has been fuel injection. The first production version appeared in 1980, on the KZ1000G Classic. It worked, despite our skepticism. Kawasaki's system was based on the L-Jetronic system developed by Bosch, in Germany, and earlier seen on Datsun cars, in fact Kawasaki engineers checked Datsun's service experience when they were wondering about all those sensors, the mysterious black box, the miles of wiring and so forth.

The 1981 version, as seen on the first GPzl 1, worked even better. Instant cold starts, smooth all the way to valve float, crisp throttle response, no lag or stumble, everything the engineers promised.

Engine output being assured, the 1981 GPzl 1 got frame modifications based on superbike experience. More steering rake, two inches added to the wheelbase, low bars, rearset pegs, an oil cooler, air-assisted forks, adjustable damping on the shocks, bright red paint with silver and dark blue trim, black paint for the engine and matte black for the exhaust system. Everything in the sports department catalog, in sum.

The bike was wonderful. It was designed and styled and suspended for performance and we said every good thing in our book.

But that's now history. Kawasaki introduced the GPz550 and then the GPz750. Both were done in the same lines as biggest brother, in that they got more power from tuning rather than extensive redesign, they have red paint and black engines, an angular style that flows tank into seat into rear section with—shades of Z-l again—just a hint of the traditional ducktail.

The major news for the 1982 GPzl 100 is that the fuel injection has been modified. A lot.

Probably no layman can really understand all the details of any electronic system but as nearly as we can decipher the book, a carburetor works because air flow across a restriction lowers air pressure and the pressure drop pulls fuel into the air stream. Fuel injection has no such restriction. Instead, there is a fuel pump and that pump pushes—injection, get it?—fuel into the air stream,. In this case the injector nozzles are just upstream from the intake valves.

Now. In a sense, fuel injection is a way to get more performance indirectly. Because there is no restriction in the intake tract, as in carbs, the engine should be able to flow more air and thus develop more power.

That isn't the purpose here. Instead, a carb is set at the factory to deliver so much fuel for so much air under such-and-such a throttle opening. It averages out, you might say, and because there are so many variables, like air temperature, throttle demand, engine speed, air density and so forth, the mixture is seldom quite perfect. Further, if you want lots of safe power you calibrate a touch rich and if you're required to certify a certain level of exhaust emissions, you calibrate lean. In the case of motorcycle engines the engineers have recently had some, er, lean years but now have pretty much gotten control.

Fuel injection's promise is that the engine will run better. The engine's demands can be more precisely calculated and the fuel delivery more precisely controlled. So the mixtures at hot, cold, idle and wide open can be right on the mark. That EFI can meet the emissions requirement and deliver optimum mixture for safe power, at the same time is why the performance comes as an incidental.

Kawasaki's first unit was impressive. The second was simpler and better. It's almost embarassing to read the '82 specifications and learn how much room there was for improvement.

Still skipping lightly over the long words, the '82 system is named DFI, for Digital Fuel Injection. The name change is because the '81 used an analog signal processor and the '82's is digital, with smaller and fewer parts.

Next, the L-Jetronic had an air flow meter well upstream from the injectors. This restricted flow while measuring it. DFI has a throttle valve sensor, a remote way to measure flow while being less restrictive.

Key to EFI is the sensors, devices that measure various conditions and report to the microcomputor, which in turn tells the injector nozzles how much fuel to pump into the air stream. The L-Jetronic has sensors for airflow, engine speed, battery voltage (actually a means of correcting for voltage change. The signals are electric.) and temperatures of the engine and the incoming air.

The DFI has sensors for throttle opening, engine speed, battery voltage, engine and intake temperature and ambient air pressure. DFI, the Kawasaki technical men say, takes more pulses while being lighter, simpler and thus less liable to failure and has less intake resistance.

Moving on to the rest of the machine, the most visible change is a quarter/ Café/sports/bikini fairing, like the one introduced last year on the GPz550. The '81 GPzl 1 had an instrument pod, informative but not especially attractive. The '82 has a new panel tucked behind the fairing. It contains tach and speedo, instant trip reset and voltmeter check, a fuel gauge and monitors for sidestand, fuel and battery level. They are linked to a small warning light. And there's the neutral and high beam signals. The handlebar pedestal has been replaced with a cast bridge behind the top triple clamp and the bars are two stubs, clamped in the bridge. The bridge/clamp looks as if it pivots, to adjust the angle of the grips, but it doesn't. Levers are dog-legged and the brake master cylinder has a sight gauge. The steering head lock is in the switch. Bars and mirror stalks and most of the hardware and controls are painted or chromed black, as are the mufflers, passenger peg mounts and nearly everything else that's chrome on a standard bike.

Modifications include new material for the disc brake pads, larger front brake rotors, a remote filler that also links the air-assisted forks, reinforcement for the swing arm and a seat with more padding.

Tires are slightly larger, 100/90V-19 in front, 120/90V-18 in back. Standard tires this year are Dunlop K300-TL, the upgraded original equipment models first seen on the GPz750. Primary drive and internal gear ratios are unchanged but the rear spocket has one more tooth (42/15 for the '82, vs 41 /15). The engine spins a few more rpm faster in any gear, at any speed.

It should also spin faster, longer than last year's 1100 because the roller bearing crankshaft has been strengthened. Closer tolerances on the press-fit pieces should eliminate the tendency to twist cranks when a shift is missed.

No horsepower claims are made nor figures given. Perhaps a reluctance to alert the Wrong People? An educated guess based on Kawasaki Fours and the trap speeds turned by this bike would be 100 bhp plus one or two on a good day.

At the drags, we have a nearly dead heat.

The '82 GPzll weighs 559 lb. with half a tank of fuel. The 1981 weighed 551 lb. The 1981 Suzuki GS1100 weighed 557 lb.

Elapsed times for the trio were 11.18 sec. for the '82, 11.18 sec. for the '81 and 11.10 for the Suzuki. Top speeds with a half-mile running start were 136,135 and 135. Races are decided in inches, sometimes, so the Suzuki retains the E.T. trophy but with the same rider on all three, it's even money when they come to the line.

There's genuine improvement in a more useful area. Last year's GPzl 1 was troubled by overly sensitive front brakes. They locked without undue pressure and faded under repeated maximum use. The double discs came from the KZ750 and the leverage, the force exerted on the tire by the brakes in response to input from the master cylinder, wasn't properly controlled. For 1982, there are pads of a new material and the rotors are larger in diameter, giving them more torque with which to resist the input.

Equal performance with a (slightly) heavier bike comes from, we suspect, a few more horses and from changing the gearing. Spinning the engine faster aids acceleration but means a small loss in efficiency; at the same road speed the engine is turning faster but working less to move the bike down the road and more to spin the engine against its own nearly closed throttles. Thus, on the mileage loop the '82 did 45 mpg while the '81 did 52. No big thing. What we like better is that the GPz can be ridden, at normal road speeds, 200 mi. between fill-ups.

But enough of figures. The real pleasure of DFI begins on a cold morning. There is no choke, nor even its modern equivalent the enrichening circuit. The sensors for air and engine temperature take care of that, no human hands needed. Instead there's a fast idle lever on the throttle shaft. Flip that up, turn the key, pull in the clutch lever, thumb the button and the engine is running. It will start and idle with the lever off but it's easier to dial in enough speed to keep the engine busy, then nudge the lever toward off as the engine warms. One can ride away immediately but even if the mixtures will allow it, mechanical sympathy for those cold gears, the still-stiff oil, etc. make warming up a nice thing to do.

Enters now some human frailty. A carburetor is a fairly complex device. If you tot up all the various functions it performs, most of them well, carburetors are busy and sophisticated. We fear them not, indeed all too often we overstep our talents and maintain them to death, but for most bikers carbs hold no terror.

Contrast that with fuel injection. Electronic Fuel Injection. With printed circuits and relays and thermocouples and all the rest. EFI isn't much more complicated but while you can look at a carb and know—or think you know—what does what, all you get from staring at the box of microcircuits or the wires and fittings for the sensors is a feeling of inadequacy. Not many people like that feeling and not a few bike nuts are resentful of things they can't tackle at roadside.

Thus, when the test bike turned out to be not perfect, when relentless experiments showed that if you whack the throttle full open from idle the engine sometimes will die, and when a slight surge manifested itself at cruise on light throttle, somehow the office romantics liked EFI better than before. It isn't smarter than us and we can accept it. Like the ancient Greeks who threw the Senator out of office because they were sick of hearing each other say how just he was. Human nature.

For the emotionally mature, a conclusion: this is the fourth EFI we've had. Nothing has gone wrong with any of them. While conventional carburetors and ignitions deteriorate with time, electronic systems don't. They're go or no-go. Failures are random. They may come one million miles down the road or as you proudly ride out of the showroom. Because none have occurred, we're willing to accept the idea in principle. Those who don't want EFI are reminded that there are 200 models on the market, 198 of which have carburetors. What the antique restorers of the future will do for parts, we leave to the antique restorers of the future. And those who want EFI can buy it.

What do they get? As mentioned, there may be some slight gain in power. There will usually be better manners on cold or hot starts, at high elevations, anyplace the carb's built-in latitude is exceeded by conditions.

And EFI makes the GPzl 1 run beautifully when you aren't trying to catch it with its relays down. Crisp and instant throttle response, clean power all the way up, revs as quick as you can move your right hand. The engine, highly tuned as a street engine can be, can be lugged down to 1500 in top gear and it will pull away without protest. Not a few big Twins,

which tradition tells us are the best for torque, will hiccup the rider over the bars before they'll do that.

Ride is in keeping with the GPzll's character. This is a sports bike, no apology. The ride is firm. Not harsh, not even stiff, but firm. All motions fed into the chassis by bumps or holes or cornering or braking forces are controlled. There is some tuning provided by the air-assisted forks and the damping and spring preload on the shocks, but our big fast riders never found it too soft and the lightweight cruisers never made it too firm, not without pumping the forks beyond their normal settings.

Now. Full stop. A few words about speed, handling and respect.

During the test an enthusiast bystander spotted the GPz, identified it and knew what it would do. "Wind it out!" he shouted. We politely declined.

The GPzl 1 can be ridden all out in urban or suburban situations, just as you could sight in your 30-30 deer rifle in the . back yard. But in both cases the laws of average or the land will catch you and get even.

It is so fast! Not the usual sort of deceptively fast, the kind where you look down and learn you're going twice the rate of knots you thought. The deception is that the rocket will blast forward so quickly, so effortlessly that there are no gaps in traffic. Roll it on and you are there with just enough time to roll if off.

Handling is excellent if this same idea is kept in mind. The old Triples were short-whee\base, front-light darters. The first Z-1 s would bite back as the front tire would let go on short notice.

That's all over now. The GPz is stable, a predictable platform. At the track the best suspension settings were 20 psi in the forks, #2 rear spring pre-load and #3 damping. We checked for touch-down points footpeg on the right, peg and centerstand's foot on the left without throwing the bike away or even coming close. It's remarkably good on the straights, with no wobble right up to 135 mph. We could even accelerate in places where the average bike would only allow the rider to hold steady and hang on. The GPz is big and you can't flip from side to side but it handles transitions better than anything its size has a right to do.

The caution comes from the power and the tires. They are good tires, especially for original equipment. But the rear wheel is an 18-incher while rival cannons have a 17 and a larger footprint. Too much power coming out of a turn will slew the rear wheel out as the mighty engine overpowers the rubber. Train this tiger in tiny steps.

Tire wear? Don't ask. Through no fault of the tire itself the massive torque ground away the outer righthand tread blocks after six or seven hot laps. The left edge wasn't in much better shape. This isn't road riding and it's surely not going to happen there, but it does illustrate the need for circumspection.

Ergonomics were fine for the entire crew. The seat is softer than before and wore well. There's a slight step but it's far enough aft that there's room to move around. It may even go unnoticed until it's time to crouch into serious speed and then the step keeps the rider in place, just as it should. The small fairing is looked over and directs some wind blast at the median rider's shield and shoulders but the chest is protected. Headwinds can be ignored and fast cruising is less tiring because there's no need to grasp bars and tank against the rushing air.

Criticism approaches fussiness. Because this is a wide powertrain the pegs must be high to allow the cornering clearance justified by the tires and the suspension. The pegs are rearset, with a remote shift linkage, the pegs fold readily and the sidestand seems farther outboard than it needs to be. So, taller riders may find their knees angled and several riders reported kicking the left peg up while threading feet into position. Practice took away most of this, but still. . .

Kawasaki design sometimes falls between overprotective brother and cranky elderly aunt. The starter has a lock-out so you must pull in the clutch lever even if the gearbox is in neutral. There's a rolling-ball system in the shifter so when the bike is standing still and the gearbox is in first you must get neutral. The lever won't go into anything else. There seems to be a trade-off here. The test bike was difficult to slip into neutral when rolling, a flaw not seen in most production bikes for 10 years or so. The new rider's handbook says select neutral while rolling, right?

The instrument panel contains a fuel gauge. As the last little square empties, a blinking light comes on. A small light, but still. The test bike went on occasional blink at 160 mi., fulltime blink at 175 and needed to be switched to reserve at 200, with another 20 or 30 mi. worth of gas still in the tank.

Do we really need to know this much? The old reliable technique of zeroing the trip odo on fill-up and learning how far you could ride is still available. If we have

a choice between too much data and too little, as with the Honda V45 Magna that doesn't have a reserve position or a fuel gauge, we'll take too much.

Even so. No one can seriously argue for the right to spin the starter with the bike in gear, or to ride away with the sidestand down, or run out of gas or get 2nd gear when you wanted neutral. And yes, bro, I know my chances of being a rock star are between infinitesimal and none and yes Aunt Mildred 1 should take my raincoat just in case. How about letting me make my own mistakes, okay?

Mistakes. When the tidy and informative instrument panel was laid out, it was done by the experienced men. The junior partner, the one who wants to do the whole bike by himself, jumped up and down and pestered until they told him to go in the next room and do the buttons for the GPzl l's controls.

Or so it seems. The big plastic rockers for starter and horn look out of place and the turn signal switch is a narrow bump with no notch for the finger, while being so far from the grip that medium-size hands must move off the grip and over and back to switch on for a left or off for a right. Clumsy and a bother in lane changes. The gain here is that the talent freed from button detail did the nicest set of easily adjustable mirrors, ones you can move this way and that without the whole thing coming loose and spinning in the wind, in our experience.

And that takes care of the debits.

The GPzl 100 is a serious motorcycle. It's chunky and strong and honest. If you get in trouble you'll have been working against the motorcycle rather than with it.

Commenting on our times, this model year has been concerned with sporting middleweights, with unusual engines and drivetrains and suspensions and whether or not the two big factories that haven't announced turbos will join the two that have. Seems like yesterday the four-cylinder with displacement running into four figures was the maximum engineering and the best way to performance.

Don't rip down the monument just yet. The exotics and turbos have a long way to go before they can match the Big Fast Four. D

Source Cycle 1982