I went through a phase when on every take off I just had to wheelie the bike for 50 yards or so. I found the way the machine reared its front end controllably and rapidly was most impressive. When you're 18 and out to impress the world this kind of delinquency quickly takes hold. I was weened off this when, after 1500 miles, both the chain and clutch were shagged out.
The 1988 GPX600 was two years and 50,500 miles old when it came into my possession, generally in good condition and with a service history of sorts - the carbs and valves had been done every 10,000 miles and the owner had earnestly assured me that he had changed the oil every 1000 miles. The engine was a bit rattly but then that's how most watercooled, across the frame DOHCs Kawasakis sound.
My first impression of the machine was the way it accelerated, then the ease with which it could be flicked through fast bends and almost my last impression occurred when I then decided to find out its top speed. With 140mph on the clock down an empty, straight country road, a tractor rolled out from behind a hedge. An adrenalin inspired grip on the front brake lever had the forks plunging despite the anti-dive, whilst the back wheel locked up and skipped all over the road. The farmer looked up from whatever it was he was contemplating, slammed on his brakes, leaving me a foot, or so, in which to slip through on the bouncing Kawasaki.
As this occurred on my very first ride I made a note to think about what I was doing a bit more, then promptly forgot that by experiencing a series of hairpins that the GPX went around as if on rails. The seat leaves you low in the machine with that big hump of a tank between your knees and the bars a reasonable stretch away, not so high as to be instantly uncomfortable in town. I felt immediately at home on the machine and after ten minutes it was like I had been riding the bike for years.
The first 6000 miles went by with hardly any problems. Only a rear Metz that seemed to wear out as soon as it was placed on the wheel spoiled my happiness. A wider tyre was fitted which improved mileage slightly, from 4000 to 5000 miles. The front was slightly better at 8000 miles. I like the Metz's, though, they had great grip even in the most dubious conditions and endowed the bike with first class stability. I did ride a friend's GPX fitted with Pirellis but it felt very twitchy, so I think I made the right, albeit expensive, choice.
When I bought the bike it was still on original suspension, all turned up to their highest settings. With about 58000 miles on the clock, the shock was shot, allowing the machine to pogo over bumps and wallow through the curves. As the rear tyre wore down to the carcass the weaves became more pronounced and accelerating out of corners resulted in much wobbling of the handlebars. Before I got around to replacing the shock and the tyre, the machine had become really dangerous above 70mph. The transformation when the replacements were made was almost miraculous, the Kawasaki felt like a brand new machine.
Not for long, both the front calipers and anti-dive unit conspired to seize simultaneously. With just under 60,000 miles up, they all needed replacement. Thank god for breakers, as new parts were very expensive, although some items common to the whole range such as indicators and levers were rather more reasonable. The pads lasted about 9000 miles which I though reasonable as I tended to ride on the front discs a lot - my right-hand muscles bulge magnificently from all the effort required.
With 64000 miles under its wheels, the handling started to degenerate again. There are a couple of grease nipples on the Uni-track which I had occasionally attacked with a grease gun, there was no discernible movement out back. The front forks were not pitted and there were no leaks from the seals, so that end seemed okay. The problem slowly emerged as the wobbles became really fierce. After one white knuckle ride my only surprise was that I was able to come to a stop without suffering a heart attack or being thrown clean off the machine. When I tried pulling on the forks there was a slight amount of movement - the steering head bearings were on the way out again. Perhaps because I didn't fit Kawasaki bearings, the replacement only lasted 5500 miles.
By 65000 miles the engine was running rough and spitting back through the exhaust. I feared the exhaust valves were burning away, not having checked the clearances since buying the bike, but one look at the underside of the original exhaust with several holes in the downpipes convinced me otherwise. A bit of welding got rid of the popping noises but the motor was still running rough. Taking off the GRP was a real pain in the arse, then stripping off all the muck to remove the cylinder head and then finding all the valve clearances were perfect didn't fill me with amusement. The local dealer did a carb balance, as I didn't have the equipment, and the motor was running perfectly again.
It didn't, however, have much of an effect on fuel consumption. I managed to get it down to 20mpg on some well crazy occasions, although 55mpg is possible if you're in a moderate mood. Cruising at, say 90mph, down motorways returns 40mpg, doing over the ton gets it down to 30mpg. My friend's machine is a lot lower in mileage and does about 10mpg better than mine at the same speeds.
The bike is good as a high speed tourer. The riding position is comfortable and the fairing begins to make some kind of sense above 90mph. Below that it just helps direct a deluge of water over hands and head. A German autobahn dash at 120mph didn't perturb the machine at all and I was still able to stand upright afterwards. Sustained high speed work does take its toll on the chain, which stretches so much its needs adjustment every 300 miles. Mileage has varied between 2000 and 7000 miles depending on the level of abuse and quality of the chain.
A newly acquired girlfriend was soon perched on the pillion. She was nearly as tall as myself and towered over me because of the radically stepped seat. Judging by the way imbeciles pointed at me and hooted out obscenities it might have looked faintly ridiculous. After a 200 mile run she got off the machine, swearing like a docker and telling me where to get off. She stormed off towards the railway station and hasn't spoken to me since. Thank you very much, Mr Kawasaki!
Perhaps I will have to find a Japanese girlfriend, as apart from a midget they're the only sort of girl likely to be happy on the crunched up and uncomfortable pillion perch. The bike now has 76000 miles on the mileometer. There is a slight oil leak at the cylinder head gasket, it needs a half litre of oil every 200 miles and doesn't pull beyond 125mph. The clutch has begun to drag in town and the gearbox has become very crunchy, slipping in and out of third, fourth and fifth. The neutral indicator has ceased to function and neutral has become difficult to find.
Only last week I pulled up at a crossing snicked the bike into what I thought was neutral and revved the cold engine a bit - the box jumped out of neutral and leapt forward a foot before the engine stalled. The old dear who we had inadvertently attacked, picked herself off the crossing with surprising rapidity and was joined by her fellow old crones, who surrounded me as I frantically tried to fire up the GPX. When the engine finally caught it saved me from a real battering from the ancients.
The machine still looks neat enough, so I took it down to the local dealer and asked him about a trade in against a ZZR600. He offered me a thousand notes off the list price. I told him where to stick his offer and went off on a round of the breakers to buy some much needed bits for the GPX. Looks like I will be sticking with it for a couple of more years.
Chris Leigh
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32,000 miles had done quite a lot of damage to the 1988 GPX600. The camchain rattle causing the most concern if the rotten condition of the chassis was ignored. It still ran well enough to reveal that the chassis wasn't bent and that the motor still had some life left. £975 seemed reasonable.
£120 for a new camchain to be fitted combined with £150 for a respray left only a new sprocket and chain set to put the GPX to rights. Would've been a week's work had not the mail order company mislaid my order for two weeks. It went through the MOT without any bickering from the tester.
The respray had left the bike ice-white and grey, which helped out the square cut lines of the GPX. It was always a bit odd looking even by the standards of the day but at least the large white frontal area had the cagers shaking in their seats as I roared up behind. It was quite nice being mistaken for a police bike, with cars veering viciously out of my path.
Initially, this was just as well. The front brakes had appeared rather powerful in low speed stops, but a couple of emergency braking sessions revealed them to be entirely inadequate. The calipers' pistons were sticking on and off, making the forks judder like their bushes were shot.
The rear disc was even more horrible, sticking on solid, turning the disc red hot. I hurriedly pulled it off, suffering third degree burns for my pains. A huge amount of sludge thrown off the rear wheel had found its way inside. On disassembly it was found to be beyond repair. I reassembled it without any innards....
The front calipers were cleaned up, given new seals and a set of pads. The heavily scored discs were left as they were with the result that the brake worked well enough but made the kind of screaming fit imitative of a dog being run over by a car. The forks were still in good shape with a lack of looseness that would've served a new bike well, so braking was thereafter very controllable even in the wet, with plenty of feedback from the front tyre.
The GPX had a pair of Avon tyres (AM22/23) on its sixteen inch wheels which gripped the road well enough but there was a feeling of twitchiness from the front end. It was more nervous than violent, but never seemed entirely planted on the road, especially at the high speeds that the GPX was still capable of.
The Avons were not so good on wear as I'd expected, about 7 to 8000 miles. A ME33 and ME99 combination provided even more grip, enough to ground the pegs on the faster bends, but they lasted for less than 5000 miles the pair. Another owner suggested Pirellis but a good deal on a set of Avons made me go back to them. 16 inch wheels do go through tyres faster than larger diameters.
The chassis seemed strong enough, at least until the original shock finally lost all its damping and the Unitrak bearings developed a bit of slop. This is a common problem if the spindles are not regularly greased. Removing the swinging arm was only achieved after expending enough brute force to get me locked away as a mass murderer. Shock, spindles and bushes all added up to over a £100. The set-up really needs a strip and grease every six months.
The motor runs more reliably than the chassis. It's a lovely unit with a distinct character split, that is maybe emphasized by the Motad 4-1. Below 7000rpm it's relaxed and affable, although not if less than 3000rpm is employed in any gear between fourth and sixth. Taller gears revealed a lot of transmission slop, which was not, fortunately, mirrored in the smooth gearchange (although high mileage engines can be deduced from a grabby, vague box).
Hitting 7000rpm had the GPX snarling, spurting up the road, needing a quick dab on the gear lever to keep up with the rate the tacho needle swung around the counter. The GPX could be dismissed as old tech, these days, but it still had 85 horses and not much more than 400lbs of mass. Top speed was 145mph, which meant it could easily cruise at up to 120mph, although the feel of looseness at the front and the air blast streaming off the top of low screen made it a less pleasant experience than on some grand tourer.
The bars, pegs and seat all worked well for me. The pilot's perch was nicely sculptured and held me firmly in place. The big chunk of petrol tank between my knees helped me feel part of the bike. Someone fatter or longer of leg might complain about being rather cramped but I was happy enough for 200 to 250 miles at a time. I was also more than happy with the fuel, at 55 to 65mpg!
I was less elated when the replacement camchain went after only 14000 miles. This time I put in a new tensioner as well. Somehow, during the reconstruction, some wiring had been trapped between the engine and frame. The result was the ignition module going up in flames, which scorched some of the plastic and blew every fuse in the Kawasaki.
This all occurred as I was lumbering along some dual carriageway at 80mph. By the time I'd crashed braked to the hard shoulder, I was gagging from the smoke coming up from the bike. Panicked, I ran away from the GPX, thinking the whole lot was going to go up in one big fireball. The fire died a death of its own accord, but not before three police cars descended upon the scene like starved vultures. They couldn't think of anything to charge me with.
Kawasaki ignition units are not the most reliable bits of electronic trickery in the world, nor are GPX's the most common bikes on the road. Breakers just laughed when I asked them about replacements; the only one who agreed to sell me one sent me a unit that was already dead and refused to refund the thirty quid. As it was 500 miles away I had to put him on my death list for future retribution. I ended up buying a new Kawasaki unit. Sob, sob!
Other signs of frailty were evident in heavy smoking of the exhaust on starting up, the occasional carb off-loading a bowl full of petrol and some rattles from a clutch that was becoming a bit jerky. Engine maintenance consisted of an oil change every 2000 miles with a new filter at 5000 miles as well as a carb balance and valve check.
I did, on holiday tours, stretch things a bit further than that with no apparent ill-effects. Pillions were not too amused at their tiny perch and pegs placed perfectly only for midgets. It was impossible to secure a tank-bag properly and my throw-over bags took large chunks out of the plastic sidepanels and always threatened to turn into a fireball on the side with the rakishly angled silencer.
Pillions cursed the secondary vibes that strafed their feet, although it would take over 300 miles before the buzz had any effect on my extremities. Even after 500 miles in a day the effect of the vibration was not too calamitous. As a solo tourer it was fine, two-up was pushing the limits of the experience.
By the time 60,000 miles were on the clock, the motor had started to run rather rougher than normal. I carried on riding for another 3500 miles until starting became a ten minute affair. Diagnosed as low compression on two cylinders. By then the camchain was rattling again as well. Pulling the motor apart I feared the worst, but two sets of rings and a new chain put it back into reasonable shape. The plastic needed another spray job to get the whole thing up to spec, this time in the stock red, white and grey.
The six year old bike was obviously nearing the end of its useful life by then. I knew a point would come when so many parts would need replacing that the total cost, even using secondhand parts, would not make a rebuild a viable option.
I kept riding for a while, putting nearly 70,000 miles on the clock before having to spend out any further money. I'd started to find that around 90mph it'd weave wildly and wobble savagely if I was silly enough to go any quicker. These symptoms were finally traced to the demise of the rear wheel bearings. A coupe of cheapo items were hammered in; they would last long enough to pass the MOT and let me sell the bike before anything else went wrong.
This was perhaps a little ungrateful, but I'd grown a bit bored with the GPX during the past couple of months; I'd either become used to its performance or it was losing its edge. I only got £850 for it, but all things considered I reckon I'd had the best years of its life.
Mitch