Kawasaki ZX750R

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Kawasaki-GPZ750F-84--1.jpg
Kawasaki ZX750R
Manufacturer
Production 1984
Class Sportbike
Engine
Four stroke, transverse four cylinder, DOHC, 4 valves per cylinder.
Compression ratio 10.5:1
Top Speed 218.8 km/h / 136 mph
Ignition Transistorised, electronic advance
Transmission 6 Speed
Suspension Front: Air assisted forks, 160mm wheel travel.
Rear: Single shock swinging arm, 109mm wheel travel.
Brakes Front: 2x 270mm discs
Rear: Single 256mm disc
Front Tire 120/80-16
Rear Tire 130/80-18
Wheelbase 1495 mm / 58.8 in
Seat Height 780 mm / 30.7 in
Weight 228 kg / 502.5 lbs (dry),
Recommended Oil K-tech 10W-40
Fuel Capacity 22 Liters / 5.8 US gal
Manuals Service Manual


It could reach a top speed of 218.8 km/h / 136 mph.

Engine[edit]

The engine was a Liquid cooled cooled Four stroke, transverse four cylinder, DOHC, 4 valves per cylinder.. The engine featured a 10.5:1 compression ratio.

Chassis[edit]

It came with a 120/80-16 front tire and a 130/80-18 rear tire. Stopping was achieved via 2x 270mm discs in the front and a Single 256mm disc in the rear. The front suspension was a Air assisted forks, 160mm wheel travel. while the rear was equipped with a Single shock swinging arm, 109mm wheel travel.. The ZX750R was fitted with a 22 Liters / 5.8 US gal fuel tank. The bike weighed just 228 kg / 502.5 lbs. The wheelbase was 1495 mm / 58.8 in long.

Photos[edit]

Kawasaki ZX750R Kawasaki ZX750R Kawasaki ZX750R Kawasaki ZX750R Kawasaki ZX750R

Overview[edit]

Kawasaki GPz 750R Ninja / ZX 750R










GSX750 VS GPZ 750

I was one of the few who didn't manage to cock a leg over one of the new generation of 750s we featured in the three-way test in the June '83 issue. I remember that the conclusions expressed by those who were involved in that test were mostly in favor of the muc ho flash V-four Honda and the completely revamped GSX750 Suzuki.   There was a decided feeling of reservation, however, when it came to discussing the delights of Kawasaki's new Uni-Trak GPz750.  Although the GPz doesn't sport the latest square-section frame of the Honda, or the quick steering 16-inch front wheel of the Suzi.   I liked the bike as soon as I clapped eyes on it. So when we decided to test the kWack alongside the now fully-clothed GSX, I just had to have some.

In comparison to the aforementioned cycles, the GPz750 is on the surface, slightly archaic. The 738cc double overhead camshaft engine has a family tree that goes back to the swift and bullet-proof Z650 number of the late Seventies.   Retained from that engine is the eight-valve head (other manufacturers use 16 valve heads), the same five-speed box and four 32mm Mikuni CV carbs which are common to the other models in the Kawasaki range of the same capacity. But though you may say that, on paper, the bike looks a little dated, in practice the GPz750 will see off some 900s of a not-very-old vintage, and it will live easily with the other 750s up to the quickest speeds at which most bods will ever consistently travel.

Performance is smooth and rapid and, when required, moves easily into the neck-breaking department.   If the mood takes you, a touring speed in the 100mph range is effortlessly accomplished. Top speed is (as near as damn it) 130mph, and the GPz will cover a standing quarter mile comfortably under 12.5 seconds. This is not a slow chariot.

Fast the bike is, but flexible it is not. As the engine is more of a tweaked two-valve per-cylinder job, as opposed to the four-valves-per-pot of the opposition, this bike is a decidedly revvy item. Take-off requires more clutch dip and throttle blimping than most other bikes, and it takes a little getting used to. When I first rode the bike in heavy traffic, I tried to feed in the power with the same method I had used on the GSX1100 Suzuki Katana I'd tested the previous fortnight.  But without clutch dip I nearly stalled on the lights before mastering the art.

Out on the country highways and byways, when the GPz is into gallop mode, throttle response is immediate and urgent. At town speeds and low revs, response is more like a wet fart. In town this got to be a real pain at times as constant clutch dip and gear box thrash is not what you really require. When you do move out of suburbia and find a clear road ahead, the GPz is a pure joy to ride. Power output - a claimed 86 broncos at 9500rpm - offers great dollops of passing power and willingness to over 120mph. High velocity cruising is about as effortless and comfortable as you' re ever likely to find, thanks to large amounts of rubber mounting for the engine, which continues the Kawasaki tradition of supplying superbly smooth machinery.

Whether it's two-up cruising, town scratching or having a quick blast through some tasty B roadery, the GPz steers precisely and exhibits a taughtness that allows the rider to pick a line with real confidence. The wheels are the traditional arrangement of 18-inchers back and front, so there's none of the racer-quick steering of the 16-inch at the front.

A simple aim and bank over is all that's required. In line with the traditional feel, the frame is, as seen many times before, the single duplex cradle variety. Suspension is the Kawasaki firm's latest and greatest, with the single vertical shock with air assistance, four-position damping adjustment at the back, and air-assisted telescopic forks with adjustable anti-dive up front. Kawasaki was the first of the big four to come out with a single shock and linkage system (remember the company's late Seventies crossers), so it knows what it's about.

The back end, no matter what the setting, is ideal for any type of riding you want to do, always firm yet progressive. The front has an anti-dive that actually seems to work, as opposed to being a marketing gimmick. On some bikes you wouldn't even know if it was there or not, such is the feedback. The handling is taut and will forgive the odd line change. Unfortunately, I can't say the same for the braking system of twin discs at the front with a single at the back. The GPz7 50 is decidedly over-refreshed when it comes to braking, or perhaps the designers were over-refreshed when they came up with the system. The smallest digital pressure will result in instant and vicious stopping - and often in a lock-up. In the wet it's not a game to be recommended.


As for the clutch lever on the other side of the instruments, its light and a veritable gem. The clutch, five-speed gearbox and transmission is as smooth as the proverbial babe's twin cheeks. As already mentioned, although the clutch and gearbox cop a right hammering in town, neither could be faulted. I took a ride around the twistier lanes of Kent and Surrey, changed gear more times than I can remember (it's safer to use engine braking than twin anchs), and the system never faltered.

When you do set out on a lengthy bimble, which is the best way to enjoy the GPz delights, the rider and passenger comfort matches the best the others can offer. First impressions of the fairing were that, apart from looking tasty and aerodynamic, it would be lacking when it came to combating the elements. This is not the case. Obviously the lower legs cop as much crap as they would if you were riding a naked cycle, but wind and rain resistance for the upper bod is surprisingly good. Crouch behind the bubble and the noise of the rushing air becomes almost nonexistent. Straight line stability at the maximum speed mark is exemplary, and turbulence between rider and fairing is kept to a minimum. Seating for rider and friend is well padded, and the slightly crawl-up-the-tank front end of the saddle allows the rider to tuck in when entering a bend. I've encountered few bikes with clip-ons that haven't given the dreaded wrist ache syndrome: the GPz proved to be a delightful exception. Although the bike is definitely in the sporting category, a decent passenger grab rail is supplied and positioning of the rear pegs is sensible and not, as now seems to be the trend, so high that all but the smallest legs get shoved up around the owner's waist.

Thankfully, the passion for digital speedos, masses of warning lights and other associated gadgets seems to have passed from the sport bikes and on to the mega touring models with bathtub fairings and two-way radios. The GPz750 clocks are plain, simple and functional. What warning lights there are sit atop the tank, which can be a little distracting. I like the styling. Swooping lines from the front of the fairing to the end of the neat tail-piece reflect the radical performance, and the smart wheels and all black engine ontribute to the bike's appeal.

Although the GPz750 may not have the latest 16-valve engine, or the smartest ironmonger's delight frame, it is one tasty cycle. The buzzing motor sucks more gas than the others (best 42mpg, worst 35mpg), but sports 750s are never gonna be frugal on gas if ridden in the manner prescribed. At £2299, it's cheaper than the rest, yet it's no slower or any worse looking,and its handlebars don't fall off. Need I say more?


RevelIe and the GSX score a fry and kick for goal.

Suzuki's three-quarter-litre efforts have met with varying degrees of approval since the four cylinder GS arrived in the mid-seventies to an explosion of acclaim. It was the factory's first attack on the big bike four stroke market. Weighing in at around 5051bs dry, it could hit over 120mph from a claimed 68bhp and returned 39mpg. It also cost only £1250... Compared with the other 750s it stood out by virtue of its excellent handling and serious acceleration. As the seventies drew to a close and the Orientals pandered to what they thought was an unquenchable desire for megabikes on the part of their Occidental customers, the 750 class fell into, uh, desuetude. As though wishing to kill the class off for good, Suzuki produced its first GSX 750 at the decade's end — within a year it could hardly give them away. Overweight, overwrought and undersprung it handled like an abandoned steamroller, though its motor was rightly praised. In November 1980, its official price was £1700. I seem to remember Suzuki offering them for £1200. The dohc 16-valve motor featured the TSCC (Twin Swirl Combustion Chamber) mod, 32-mill carbs replaced the old 26mm versions, CR was upped to 9.5:1 from 8.7, electronic ignition replaced the coil and contact breakers and bhp was upped from 68 to 80.

Had it been mounted in a better chassis, the early GSXs would have been in with a J chance. In 1983, Suzuki realised this, being nothing if not quick on the uptake. The result was the GSX750ES, a bike which did J very well in a giant comparisons" test with the direct and revamped opposition from Honda and Kawasaki later that year.

For 1984, Suzuki has made I only styling changes and added a "full" fairing to the 1983 model. It knows when it is onto a good thing.

So do you, when you ride it. The stepped seat seems low, perhaps because it places you in the bike, yet even with the advantage of small wheels (16in front, I7 in rear) it is a tad over 31 in off the ground. Not really low, is it? You'd expect from the styling to find the bars somewhere south of the anti-dive; instead they are raised from the headstock to provide a stance similar to the old upright bicycle position. Odd, because you are actually leaning forward on them, as persistent wrist ache in town testifies. Despite the confusion between assumptions and reality, the riding position is excellent, comfortable and poised.

The fairing is effectively last years bikini job with bottoms attached. The two halves hug the frame (aluminum painted steel, square section where visible, tubular elsewhere) like shrink wrapping, swelling a little down at the belly pan end to accommodate the rider's bootiepoohs. The fairing's upper half is still about as useful as a hankie in a hurricaine but it serves to make the bike look sharp. Pity the instruments aren't mounted on the bracket— anything the bars have to carry when steering should be mounted elsewhere if possible. The switchgear isn't all it might be either. The indicator switch doubles as the main beam switch and looks and feels flimsy. Gloved hands knock it right through from left turn to right without knowing it. The horn doubles as the passing beam (for the latter you haul the lateral switch back with the back of your thumb, ho, ho.  Should you still have the choke on -  the engine takes some time to warm up – you can launch yourself into a horn/flash/kangaroo mode peculiar to learner car drivers…..)  More thought here, please.

The niggles dissolve once the engine is warm and the bike underway. The motor is all sweetness and light — light clutch, light gearbox, smoother power — with the rasp ever present should the throttle ever need tweaking in anger. In ordinary use the flexible motor provides ample power to haul away easily from any troublesome moments. Whisk it through the gears at max power and it rockets past such moments as though on a different orbit. Wind it on from any point above 3000 rpm in any gear and it'll restore your faith in life and in the value of fun. Drop a gear and snap the throttle open and the rear tire scorches for grip as you catapult forward. Yet, delightfully, it idles at 500rpm, can be commuted in top gear and limits its expression of temperament to a slight roughness, almost unnoticed, from mid range to 8000rpm. You can feel it through the pegs. Thick soles would damp it out. The power spread is wider than a salesman's smile, the transmission smoother than a Brandy Alexander. Ridden hard it returns some 37mpg. Ridden normally it's yielded as much as 56. Overall I managed 46mpg whilst having a lot of fun.


It would be churlish, and difficult, to find fault with the engine (though, at the risk of so being, wouldn't rubber-mounting complete the good work?)

It would be hard, too, to find fault with the chassis.  The front fork has adjustable preload via a nut on the top of each leg. The handbook warns against careless settings, stressing the need for precision — I didn't find any need to adjust them in hundreds of miles of test, either solo or two up, on good or average roads. The rear end is Suzuki's Full-Floater affair. Preload is adjustable through five settings as indicated by a near-invisible pointer, but as the adjustment method is a knurled knob with no positive stop the exact setting is indeterminate between the limits. Setting two is recommended (or as near to two as you can judge). The book also recommends setting two for the four-position damper. Odd, as the dial has the third position in red, suggesting it as standard. In the event I rode mainly on the twos, bumping it up to threes for passengers. Solo, the threes definitely made for a firmer ride. In the interests of science I should have tried a 5/4 arrangement, I suppose, but it takes a long time to wind the preload up. Anyway you don't expect me to relate meaningful data about each of the 20 possible settings, do you? The point is the bike will behave well as long as you adjust the rear end to allow for extremes. Two 13 stone bodies need a little more beef beneath them than one seven stone slimline tonic. The Suzi supplies whatever combination you require.

I found the 16 in front wheel a mixed blessing. In slow corners it is difficult to prevent oversteer -  the system only works when you power through bends, an impossible, not to say pretentious, concept in commuting terms. The result is a scrappy feel to slow cornering with a sort of pattering from the front wheel which reminds me of walking on sugar. Nothing alarming, just a little irritating. As usual, the benefits are felt out of town. Here the Suzi glides into long bends then clings to the chosen line. Amending it is as easy as thinking about it. On a sweeper, overtaking at high speed on slower-steering bikes usually requires good road knowledge and a kind of apexing to bring you back into the curve. With the GSX you simply flow into any trajectory that suits you at any point you choose. It is almost uncanny. But, like everything else, you get used to it so quickly that riding a slow-steering bike by comparison becomes almost a chore. I'd go for the smaller wheel any time.

I wouldn't however, go for the Michelin A38/M38s as fitted. Which Bike? has criticised these tires before, and Michelin has slapped our wrists for it. I personally hadn't ridden the tires and didn't know they were fitted until I looked to find out what could have been responsible for a heart-stopping slide experienced shortly after picking the bike up from Suzuki. I found nothing. Having no reason to suspect the tire (I've always found Michelins perfectly OK) I assumed it was unseen oil on the road. Bu it happened again. Then one day I stopped for fifteen minutes for a tea. It started to rain. At the first bend I nearly lost it (and I am careful to the point of paranoia in the wet). Yet it didn't happen again and the tires felt grippy enough the rest of the trip. After a while I began to notice that the tires would slip, or at least, the front tire would slip, when it hadn't been warmed up enough. So if you stop for any length of time, the tire cools down. Again, and this is where the risk is, if you suddenly drop into a tight bend, the tire slides, because the tread towards the edges just doesn't get hot enough in ordinary use. Warm them up and, as you can see from our Bimota shot in this issue, they stick like a pub bore. But they have to be warmed up well for that kind of silliness. In ordinary use, I found them too unpredictable for comfort.

But the tires can be changed, and with Metzelers or MKII Phantoms the bike would be unnassailable in its class. Perhaps the brakes could have a little more bite, particularly at the rear. But I had a couple of involuntary emergency stops and each time they more than did the job. And there's not a trace of grab. They're not Goldliners, but they're pretty good all the same. The minor detail criticisms could only be remedied by Suzuki, who oddly in other areas like the excellent petrol cap show a flair for good design, but they do not detract from what is, for a mass-produced machine, a lovely motorcycle. It has spirit and even a touch of class. Improve the fairing and fit a grab rail and you'd have a superb cycle. Fat chance of Suzuki knocking this one out cheap. Source Witch Bike 1985

Make Model Kawasaki GPz 750R Ninja / ZX 750R
Year 1984
Engine Type Four stroke, transverse four cylinder, DOHC, 4 valves per cylinder.
Displacement 746 cc / 45.6 cu-in
Bore X Stroke 70.0 x 48.6 mm
Cooling System Liquid cooled
Compression 10.5:1
Lubrication Wet sump
Induction 4x 34mm Mikuni carburetors
Ignition Transistorised, electronic advance
Starting Electric
Max Power 92 hp / 67.2 kW @ 10000 rpm
Max Torque 7.2 kg-m / 52 lb-ft @ 8500 rpm
Transmission 6 Speed
Final Drive Chain
Front Suspension Air assisted forks, 160mm wheel travel.
Rear Suspension Single shock swinging arm, 109mm wheel travel.
Front Brakes 2x 270mm discs
Rear Brakes Single 256mm disc
Front Tire 120/80-16
Rear Tire 130/80-18
Wheelbase 1495 mm / 58.8 in
Seat Height 780 mm / 30.7 in
Dry Weight 228 kg / 502.5 lbs
Fuel Capacity 22 Liters / 5.8 US gal
Consumption Average 36 mpg
Standing ¼ Mile 12.4 sec / 106 mph
Top Speed 218.8 km/h / 136 mph