Kawasaki GPz 600R Ninja / ZX 600R Ninja




Make Model

Kawasaki GPz 600R Ninja / ZX 600R Ninja


1985 - 86


Four stroke, transverse four cylinder, DOHC, 4 valves per cylinder


592 cc / 36.1 cu-in
Bore x Stroke 60 х 52.4 mm
Cooling System Liquid cooled
Compression Ratio 11.0:1
Lubrication Wet sump


4x 32mm Keihin CVK carburetors



Starting Electric

Max Power

75 hp / 54.7 kW @ 10500 rpm

Max Power Rear Tyre

69 hp @ 10500 rpm

Max Torque

5.1 kgf-m / 36.8 lb-ft @ 9000 rpm


6 Speed 
Final Drive Chain

Front Suspension

37mm Air assisted forks, AVDS adjustable anti-dive
Front Wheel Travel 140 mm / 5.5 in

Rear Suspension

Single air assisted shock adjustable for rebound damping
Rear Wheel Travel 130 mm / 5.1 in

Front Brakes

2x discs 1 piston calipers

Rear Brakes

Single disc 1 piston caliper

Front Tyre


Rear Tyre


Dry Weight

195 kg / 430 lbs
  217.0 kg / 478.4 lbs

Fuel Capacity 

18 Litres / 4.7 US gal

Consumption Average

47.8 mpg

Standing ¼ Mile  

12.7 sec / 107.3 mph

Top Speed

205 km/h / 127.5 mph

The Ninja 600R was the name given to the Kawasaki ZX600 line of motorcycles sold in North America. In Europe it went by the GPZ600R (1985-90) and GPX600R (evolved model, 1988-97).

With minor variations over the years, in 1986 the GPX model is released with major changes, like a new double cradle frame, a different anti dive system (ESCS-Electronic Suspension Control System) improving the AVDS (Automatic Variable Damping System) from the GPZ. Also, the GPX brought more power (84 hp against 76 in the GPZ) and a higher top speed (140 mph against GPZ's 135 mph)

In the years we promise to provide you with a continuous stream of new models that will take the state of motor cycle art to unprecedented heights . . . thank you very much. Please enjoy inners and ..." sitting amongst the (for once politely attentive) throng desperately fighting back the waves of nausea sweeping over me, the mention of food by Dr Ohba. Kawasaki's No 1 man, spelt the final end of the evening's entertainment for WB?'s man in Spain. Legging it out of the hall under the disapproving gaze of the horde of J-model exec types flown over for the unveiling of the 600R, all I was destined to enjoy for the rest of the night was the cool comfort of the Great White Telephone. OK, so maybe I'd entered into the previous night's revelry a little too enthusiastically, inspired as I was by the tales of dubious deeds and alcoholic excess that seem to be a feature of all foreign trips. But no more so than some of the admittedly more experienced liggers amongst us. Besides, I'd already spent the day mastering a force 10 hangover. Fortunately a Spanish quack's diagnosis of food poisoning quickly stilled assertions by my gossiping compatriots that the feeble Dabbs nerve had finally snapped.

Kawasaki had chosen Jarama racetrack just outside Madrid as the venue for the testing of their '85 range. But after my involuntary intestinal exercise of the night before, breakfast at the hideous hour of 7.00am before the coach trip to the circuit held no appeal whatsoever. So it was early afternoon before I finally arrived at the track decidedly the worse for wear after a nightmarish journey with an Italian driver through Madrid's streets. As well as the 600R three other models were neatly lined up in the pitlane, rather like victims before a firing squad; the GPz 750R, KLR 600 electric, and the LTD 450.

Fortunately the Brits weren't scheduled to ride that day, so I was able to watch the crazy antics of the French and Germans from the safety of the Armco. What struck me most as a bemused spectator wasn't the rapid progress of the GPz's but the way the KLR's were being flung through the corners by the French. Apart from a starter motor the '85 KLR is supposedly identical to the '84 model but I don't remember Willis telling everyone how he'd worn out his jeans going through Hyde Park corner 'cos that's what the French were doing around Jarama, clipping apexes with their knees on the kerbs and trouncing several unwary chaps on GPz's in the process. Dunlop K750s may be knobblies but they do an excellent job on the track.

Surprisingly enough not one bike went down the road on the Monday, so it was up to the Eyeties and Brits to maintain the tradition of journalistic stupidity. To try and minimise this risk the GPZ 600's were being let our in batches of eight and led round in an orderly fashion for the first couple of laps by one of Kawasaki's demonstration riders. When my turn came to ride the 600 who should lead the wobbling procession out of the pit lane but Kork Ballington who, having already ridden the 600 earlier in the year had come down to show us what it could really do. Having already spent most of the morning haphazardly lapping the circuit  even at the staid pace of the 450  I pushed my way to the front of the queue and tucked in behind the man. I can honestly say I learnt more in those two relatively gentle laps than in the rest of the day's scratching. Most of Jarama's bends seem to come in pairs and to get round quickly you've got to dive in incredibly late letting the bike drift right out to the dirt for a powerful drive out of the corner. At least that's what you're supposed to do. I was taking about six different lines from apex to exit, I only managed to get away with such crass behaviour because of the 600's wonderful steering. A short wheelbase and 16" wheels front and rear meant I only had to think about changing line and it was done, yet pulling round a slow hairpin didn't reveal any twitches or tendency to tuck in — it really is a superbly balanced motorcycle.

Coming through Tunel, a fast right hander before the long pit straight, Ballington really began to pour on the coals. Any fule can open a throttle so I followed suit. Feeling really good as we sped past the pit entrance, past the pit exit, past where I'd begun to brake the last time, and then almost past the corner before Ballington brutally hauled his anchors on. I'd started stamping and grabbing every lever in sight about 20 yds earlier. Apart from giving me more gut trouble this episode served to illustrate how good the GPZ's brakes were, even when operated in blind panic they scrubbed off the speed with the minimum of fuss but maximum feel. And the AVDS, transplanted straight from the 900R, kept the bike stable enough for me to get round the corner just in time to wave goodbye to Kork while I tried to find the right gear. 'Cos there's no doubt you'll pay footsie with the gear-lever, not because you really have to, there's enough torque for the mill to pull well from only 2000rpm in top, but because you'll want to. I could almost feel the whole bike urging me to snick down a gear or two and crack open the throttle to try and push it to its limits.

There can be no doubt that Kawasaki's engineers have paid great attention to minimising size and weight. Although the bottom end is based on the GPz 550, the crankcases have been tidied up with increasing use of alloys and plastics to reduce weight. The alternator has been reversed to lessen engine width and the crankcase breather repositioned to cut down length. Around this compact unit they've wrapped a fully triangulated double cradle frame which uses rectangular section alloy throughout. Although Kawasaki has joined the marketing game that demands they 'Name that Frame', thankfully they've decided against emblazoning such earth shattering info as 'Perimeter frame' across the bodywork a la Yamaha. Such a tight frame married to fairly high set pegs endows the GPZ with a prodigious 51° of lean — although some riders claimed to be dragging the undercarriage constantly, this was mainly due to their porcine build and the soft state of the suspension which was set at standard throughout the test session. Despite this, there was only ever the merest suggestion of a wobble when I smacked a large bump well cranked over.

In keeping with the philosophy that 'light is right', the 600's full fairing is almost entirely composed of ABS and PBT plastic, with only a single alloy bracing beam running across its front. As well as being light the fairing is more aerodynamic than most with even the traditionally 'bolt on' parts, mirrors and indicators, shaped to minimise drag. Seat of the pants testing out on the track seemed to bear out Kawasaki's assertion that the 600R is one of the 'cleanest' road bikes around as there was never any feeling of instability at high speed. If anything the bodywork added to the stability and grip of the Dunlop K825s which were tremendous even at acute angles of lean. Only when I was extremely ham-fisted with the throttle did the rear tyre step out, even then the slide was only mildly heart stopping.

At Leguna Seca last year the 900R became the Press Darling and went on to be a top seller. So it was rather a surprise to find the 750R, essentially a sleeved down 900, firmly overshadowed by the 600R. Down the pit straight the 750 was hard pushed to make any ground and it would invariably lose it again under braking, despite a 17hp advantage. Peeling off into bends the 750 felt pedestrian after the 600R and needed to be lined up far more precisely. In retrospect precision was the reason behind the criticism aimed at the 750, as around Jarama most people were anything but precise — behaviour the 600R forgave far more readily than the 750. Fact is, with two evenly matched riders aboard the 750 was just as quick as the 600R in spite of its relatively limited ground clearance, slower steering and greater bulk. Tyres, brakes and suspension were every bit as good as the 600's. And if Tokyo's young Turks have a hankering for the 750, of course with replacement 900R sidepanels, why should Kawasaki complain?

Either a lot of people have been winding up Kawasaki or against the odds the Custom boom still exists, 'cos large numbers of LTD 450's are due in this country soon and Kawasaki is confident of selling out. The cruisers amongst us could do a lot worse than choose the 450. The 'half a 900R' engine produces grunt a-plenty-low down and with 50hp on tap it's no slouch. Provided I refrained from scratching through the corners, the LTD's handling was surprisingly good. A big plus for me was the use of belt drive, the sooner more bikes possess this the better.

Whether the 600 will cope with the less rarified atmosphere of our wet and greasy roads as well as Jarama remains to be seen. But two days at the track did serve to illustrate the benefits to be gained from well designed aerodynamics, minimal frontal area and a thorough approach to detail design. Due in this country in February/March, the 600R seems set to take over from the GPz550 in the middleweight class, provided the market can stand a price tag in the region of £2700. Still, I reckon it'll be able to take on the likes of the RG and RD500s so it must be worth the dosh. E2J

Source Which Bike? 1985