I needed some fast wheels quickly, had three grand to play with and a liking for Kawasakis. Past experience with horrible strokers have put me off those things for life, however much fun 350LC owners might have. A 1988 Kawasaki GPX750 was on sale for £3650 at my local dealers. I had a test ride was impressed and offered the dealer the dosh in used fifties. For £3000 it was mine, but with no warranty at that price and I had to sort out the worn out Yokohamas myself.
The ride home was made more interesting by a massive downpour. The worn tyres gave the bike a very skittish feel, the gearbox kept missing changes and the front wheel slid away from under the bike a couple of times. Luckily, the latter occurred at low speeds and a quick flick of the GPX had it back on course.
The next day I rode down to my local tyre discount centre and had them fit a Metz ME33 front and ME99 rear. I was not too impressed by this combination, the 16 inch front wheel felt very twitchy indeed and on long, fast straights once more than 90mph was on the speedo the bike weaved quite nastily. It's possible to get that speedo up to 150mph, the weave doesn't become any worse.
The GPX looks quite weird and does not inspire much love with the great unwashed. Those looks hide scintillating performance that will see off the latest 600s and give some 1000cc wonder bikes pause for thought, especially when some curves are involved.
Despite the twitchiness, the bike is very flickable indeed. My mates on their ridiculously outdated twin shock fours didn't have a hope of keeping up with me. In the wet it's extremely easy to lose the back wheel when accelerating out of corners and it's even possible to waggle the back end on straights! Great Fun!
After 3000 miles both the Metz's were wasted and the handling had become very dodgy. Next, I tried a set of Michelins, an A49 front and M48 rear. Much to my relief, these made the steering more stable and got rid of the weave until 110mph was up, although it did get progressively more frightening if you went any faster. Apart from the weave, high speed cruising was limited only by ones own regard for licence endurance as any speed up to the maximum wallop could be considered a suitable cruising velocity. The skimpy full fairing gave a surprising amount of protection if you were willing to wrap yourself around the machine.
I used the machine to blitz Europe a couple of times without problems, although the seat does turn to a plank after the first 250 miles. Cruising at the legal 70mph is a breeze, the engine feels like it is just ticking over and the fuel improves to around 60mpg, instead of the more normal 45mpg. Once or twice I managed to get it down to 40mpg, but this was really pushing things and equated to rushing around in the lower gears with the rev counter in the red.
Power delivery is very useful. There's little indication of the arm wrenching available at higher revs if you keep it below 5000rpm. Under those conditions, the engine is smooth, will pull high gears after a fashion and dead safe to ride in the wet. It would take off in second of you had a mind to and would roll forward just by letting out the clutch slowly without touching the throttle in first. It was so easy to ride that my woman was able to master it very quickly (more normally mounted on a GS125) and I found it very interesting to ride pillion with her ass rubbing up against my crotch.
Once 5000 revs are up the thing begins to wail nicely and by the time seven grand has passed it's all but trying to pull your body apart with the G- forces. Fast forward progress is somewhat spoilt by the sloppy gearchange and if I had a tenner for every time I've missed third to fourth I'd be very rich indeed. Despite sending the revs soaring into the red every time a false neutral has been hit, the sixteen valves have shown no signs of hitting each other. Thank God.
The bike had 15000 miles on the clock when I bought it and I've at least doubled that. I say at least because the speedo cables keep breaking so it's anyone's guess how many miles have gone unaccounted for. Engine reliability has been excellent despite the fact I've never looked at the sixteen valves, never touched the four carbs and have restricted my maintenance to changing both the oil and filter every 1500 miles. The coolant level has never even flinched. The four cylinder engine had been modified to stop carb icing and there was no sign of this.
The rear Michelin lasted 4250 miles and the front was almost finished as well. I next tried a set of Avon radials. A bit more expensive but there you go. The first few miles were jolly disconcerting as the bike felt like it was running on a very thin strip of rubber but they soon settled down. High speed stability was yet better with the weave gently coming in at 125mph and not becoming frightening enough to make me back off from 150mph. Most of the twitchiness had gone as well, although the bike had started to pogo about a lot as suspension at both ends was becoming shot.
One thing with the Avons, though, if you take your hands off the bars at low speeds, the bars twitch from side to side quite alarmingly but settle down as soon as you touch the bars again. Felt just like there was a loose bearing or bolt somewhere but it was still there after I tightened up all the bolts a little more. I played around with tyre pressures to no avail.
At about 21000 miles, the rear caliper seized up so badly I had to buy a nearly new one from a breaker. The rear brake had never been very good, taking ages to work in the wet and then locking up the wheel; I had some wild slides until I stopped using it. The front twin discs were powerful and needed loads of muscle to work - I like that kind of set-up as it provides a margin of error if you grab too much brake in panic. A complete set of pads lasts 6000-8000 miles depending on riding style.
The bike also began to require lots of polishing to stop rust breaking out everywhere. Tedious and time consuming. It was also necessary to check over the bolts from time to time. The engine was generally smooth, but full bore work brought out some pretty fierce vibration. Among other things, I lost two handlebar mount bolts, one footrest and an indicator lens. Perhaps Kawasaki were trying to appeal to old Norton owners.
I fell off twice, both low speed shunts when cars did weird things I didn't expect. I cracked the bellypan in one accident and bent the right handlebar in the other. The bar snapped off when I tried to straighten it, so it was welded back on, which with a bit of silver paint makes it difficult to discern. The bike tends to slide along on the plastic and indicator stalks, so is quite resistant to serious accident damage.
The back wheel bearings went at 27500 miles, no grease could be found so it's not surprising. I had already whipped out and greased various spindles in the back end Unitrack, so had no problems in that area. A new set of springs and set of gaiters were added to the front forks, which tightened things up nicely there. It no longer bounced up and down vividly whenever I hauled on the brakes at low speeds.
The radials have done nearly 8000 miles and are due for replacement, a mileage that more than compensates for their extra cost, although my slightly more mature riding style has given them a easier time than earlier tyres. They have become a bit vicious in the wet, the rear losing grip momentarily on a few occasions but they are impressive tyres.
If you can take the looks, the GPX is a most impressive motorcycle to own, great fun to ride and even more reliable than most modern Japanese fours. I was tempted to trade in for a newer bike, but the local dealer made such an insulting trade in offer that I gave up that idea. It looks like I will be keeping the bike for a few more years.
F.J.P.
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Speed was the only thing on my mind when I went to look at the GPX750. As an eighteen year old graduate of the TZR125 school of learning (derestricted to about 30 horses, natch), what else was there? Luckily, one of our mad number had sussed out the insurance dilemma with enough artistry to survive a cursory examination by the cops. So that major limitation was overcome; a potential horror that had severely slashed the cost of most 750's on the used market.
1989, 22000 miles, shagged chain, good tyres, loud exhaust, cracked plastic, faded paint and one hell of a kick in the guts from the DOHC watercooled four cylinder mill. After I stopped gibbering away, the ton on the clock through the town centre even shocking me as I tried to stay on the pillion, I said I'd have it. Another half hour of madness on the pillion to get me home where the loot was stashed. The old man nearly bit through his pipe when he clocked the size and power of the monster but seemed happy enough to drive the owner home in his Corsa.
Fortunately, my mates were off annoying the Scots for a couple of weeks, giving me the chance to get to grips with the big Kawasaki before I had to prove how much better I was than them. Fully tanked up the GPX weighed in close to 500lbs, which made the TZR feel more like a moped than a motorcycle. All the wild techniques I'd employed to keep the tiny Yamaha in the frame were worse than useless on the GPX. Bloody dangerous, actually, as the tiny front wheel let loose for no apparent reason, the rest of the substantial mass trying to throw the bike off the road.
With the big Kawasaki I had to finish the braking before I threw the thing into corners. It was generally stable, at least in a straight line and through fast sweepers; ideal as a fast motorway missile. Up to 120mph, that is. After that stimulating velocity some strong secondary vibes came in that had the pegs and bars rattling away, not unlike the time the TZR's main bearings were on the way out. 140mph came up with a bit of a struggle, some weaves and a rather uncomfortable racing crouch (the screen being low enough to throw water into my chest under normal riding).
The life of my licence hanging in the balance soon caused me to back off (although fake ones are easy enough to buy). The 150mph ultimate kick had to wait for my favourite back road route. The motorway was as smooth as British roads get, the back road a fine example of council neglect, based on the presumption that anyone who didn't use the A road was, anyway, asking for it. The GPX, mass apart, had appeared pretty finely balanced to my juvenile mind. No-one would call it anything other than a bit of a pig in the serious twisties but lacking any of the danger found in old seventies' fours. I'd had a right laugh when some old codger on an original CB750 rode off the road when I'd cut inside him on the TZR.
Little did I realise that fate has a way of getting back at such recklessness. There I was, all gung-ho, absolutely revelling in the way the old Kawa rocketed through the gears, not seeming to slow in the least as the taller ratios were attained. 70, 80, 90mph all whizzed by...then the front end went a bit queasy as the ton was breeched. Next there was a total transformation of the handling, like the front end was falling apart. Lock to lock went the bars. Arms, already under pressure from the searing rate of acceleration, were close to breaking from the, er, macho handlebar wobbles.
At about this moment total panic set in. I'd experienced the odd wobble on the TZR - who hasn't - but nothing like the violence let loose by the bumpy road surface. Could this be what all the old hoodlums were muttering about H1's and Z1's? Panic resulted in me shutting the throttle and slamming on the brakes, the latter as effective as reverse thrust on a Jumbo without the trauma of the engine falling out. Old bikers will know that this natural reaction is the worst thing to do when a bike's in the middle of a speed wobble. The GPX reacted as if someone was shooting holes in the tyres, taking up the whole of the road in a feeding frenzy of wobbles.
We survived, but only at the cost of sprained wrists and running off the road on to grass verge. The GPX didn't like soft ground whilst trying to sort itself out but speed was down to about 30mph and my legs escaped being broken into pieces when I put both boots down to gain stability. Bloody hell, by the time we'd slithered to a halt, my whole body was shaking away like a druggie trying to go straight. I rode home as slowly as an OAP first time out on a moped. The solution to all the trauma was fifty notes on a steering damper. Apart from the time I blew a similar amount on a Negro hooker, the best value for money I've ever had. I don't know how the old owner survived without one.
This all sounds very nasty but it was the one really foul moment that I've had in two years and 27000 miles of hustle and bustle. We could throw in the rattling camchain at 43000 miles, as another, but there was plenty of warning and I didn't really begrudge the £120 it cost to fix.
Engine reliability was brilliant, despite being thrashed as if I was still on the TZR. Oil every 1000, carbs every 2500 and valves every 6000 miles, with the odd set of spark plugs to keep the starting up to scratch. It's not an ideal short hop commuter because the motor takes a good ten minutes to warm up; when cold there's quite a bit of stuttering and sulking. Maybe that's down to the open pipe but it runs really well once warmed up. A sure sign that it's running lean is the 50 to 55mpg - better than the TZR!
Some friends have complained about the gearbox being notchy and going off with a bang when first's engaged on a cold motor, but it's never really bother me. As long as the rear chain's in good shape. Old ones turn up a lot of noise and vibration in the transmission. I never managed more than 7000 miles out of a chain; worse still, the sprockets were also thrashed. I recently replaced the cush-drive which has made a major improvement in the transmission, maybe the chain will last longer this time around.
The secondary vibes did eventually turn the cracked fairing to dust, bits spraying off the machine one nice summer evening. The one bit of replica plastic I looked at seemed so wafer thin that I doubted it would last for a week! A similarly cracked top fairing was purchased from the local breaker for thirty quid and successfully patched up (i.e. it hasn't fallen off yet) and painted bright white (scares the shit out of cagers, can't wait to get a noddy light).
At about 50,000 miles the bike went malevolent in the wet, cutting out, surging in; wild slides and a short-cut to a sojourn in hell. Coils on the way out, used ones sufficed. Putting the leads on the wrong way around led to half a day of cursing until I finally realised what a stupid plonker I'd been. We all have these moments when the brain takes the day off.
Currently, the old gal looks a bit worn and beaten, rattles like a BSA Bantam, and won't do more than a 140mph. The taut suspension's still stock and the brakes haven't been touched except for pads (although they were uprated with Goodridge hose and had been rebuilt by the past owner). I don't do that much riding in winter. Rubber's a bit of a problem, what with sixteen inch wheels being old hat now and tyres being shredded in less than 5000 miles. I fit whatever's going cheap and can't say I've noticed much difference between makes - I do take the bike to its limits whenever I can.
Two years with the GPX has taught me to respect its power and mass. Also that experience and effort can get such an hefty hulk though the curves pretty damn rapidly - I've been known to wobble around the outside of devices like CBR and FZR 600's. And, I'm still here to boast about it, so there!
Seriously, though, The GPX is a bit of a hefty step up for a 125 graduate (especially one used to a mere 12hp), with a whole different level of power and handling to explore. The bike really needs revs to fly but runs cleanly if slowly below seven grand, so it's possible to take it gently for a couple of weeks. However, to the average teenage male, OD'ing on an excess of hormones, that's as likely as getting them to wear a condom the first time they take a virgin. You want to wave two fingers at society, kid, then the GPX's where it's at on a limited budget - mummy, I want a ZZR1100.
JD
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I'd just sold my BMW R60 for £1500 and was in no hurry to make any rush decisions in respect to a replacement steed. However, scanning the classifieds I noticed a red and white D reg Kawasaki GPX750R for £1900. I viewed the bike, test rode it and offered £1700 (already £200 over budget). The owner refused in no uncertain terms so I left forthwith but not before handing over my phone number, just in case. Sure enough, I had only returned half an hour when the phone rang and the erstwhile owner said it could go for £1750 but no less. A deal was struck!
The bike was in desperate need of a new set of consumables - chain, sprockets, tyres, rear wheel bearings, oil and filter change, fork oil seals. As I was already broke, replacement of the various worn out bits was carried out on a methodical and practical analysis basis - if it could last a bit longer it was left.
The first things to be replaced were two rear wheel bearings and both tyres. The bearings came free with the bike, the tyres I had to buy, gulp! I removed both wheels and took them to JC M/C Tyres in Derby - excellent place - and had Conti TKV's fitted at a total cost of around £100.
The existing tyres were Dunlop Sportmax radials. As this had been my first experience with sporty super grippy radials, I was most disappointed to find their grip and longevity was only as good as other well known cross-plies at two-thirds of the price. If you pay £100 rear and £80 front you at least expect them to grip. My previous experience with Dunlop Arrowmaxes on a CBX550 and a CB750KZ had also indicated that they were, er, crap. In the dry their grip was at best adequate, in the wet they were worse than a cheap and cheerful Chen Shin front tyre on my BMW. Back to the new tyres. The front was excellent for grip, the rear not quite up to putting down the power.
I checked the oil, finding it dirty. The previous owner had told me that the bike had been run on Putoline synthetic oil and changed every 2000 miles. Have you ever priced synthetic oil? I eventually paid £21 for four litres (yes, not even a gallon) for Motul synthetic. I then found that the very quiet Micron 4-1 exhaust had been designed by a college graduate and not a mechanic, the pipe ran directly underneath both the drain plug and oil filter cover.
To remove the exhaust you have to remove the fairing, radiator and possibly the oil cooler. I say possibly because I took the bike round to my parents and got my dad to flex the exhaust pipe down by an inch with his foot whilst I frantically removed the plug and filter housing.
With the oil replaced, new rear wheel bearings and new tyres, it was time to take it out for a proper test ride. The bike previously had a noticeable straight line weave at 90mph plus speeds and I'd assumed this was due to the rear wheel bearings being shot. The test ride revealed that the tyres needed scrubbing in as usual and the straight line stability was improved up until 115mph plus speeds. Cornering was predictable and fairly quick steering with the sixteen inch front wheel.
The bike could also be braked in mid-corner without running wide. Fast A-road riding showed up all the bike's bad points, on fast bends speed wobbles were always a problem when riding solo. On board, the feedback suggested that the swinging arm and frame were both flexing in simple harmonic motion against each other. Some journals advise fitting a steering damper but I didn't see the point (or have the money) when the steering didn't seem to be causing the problem.
With a pillion on board the bike's handling was almost transformed to an acceptable level. The rear shock has four hardness settings. I found to suit my size and build (6'2'' and 13 stone) that number one setting was most suitable and number three setting for pillion riding.
One particular ride I will never forget was a return journey from a relative in Leeds. I was following a rider with pillion on a C plate Yamaha FZ750 and could not keep up with him on the bends after 100mph (private motorway), not because the bike didn't have the necessary power but because the rider wasn't sufficiently trained in the art of bronco riding and was also struggling to prevent the bike from using other lanes of the motorway (well, that's what you pay your road tax for).
So, I settled for a steady 90 to 100mph cruising speed, being overtaken only by big Merc's, BMW's, reps in anything and, of course, plumbers in Astramax diesel vans trying to better the land speed record.
The actual engine's a gem producing 90 plus horsepower. The choke's typically Kawasaki, on or off, but it doesn't take too long to warm the engine up. There are two distinct powerbands, the first at 5000 revs and the second at 8000. The motor's very smooth and exceptionally quiet, to the best of my knowledge very reliable Carb balancing's needed every 5000 miles (£25). In my humble opinion, the engine is the best thing about the bike .
The quality of the frame and cycle part varies. The paint bubbles and drops off the wheels. Otherwise, paint finish's very good. The swinging arm has four grease nipples, a nice touch. The rear shock's harsh and gets worse with age. Expect a replacement to cost in the region of £200. The fairing's good quality but very expensive to replace - Kawasaki plastic screen £128! Pattern part £23. As the bike was only manufactured for three years don't expect too much help from breakers. I eventually got round to saving £80, bought sprockets and an O-ring chain, the type fitted with a split link as I didn't fancy stripping the swinging arm.
Some publications have said that the brakes aren't up to modern standards but I found them more than adequate. The front twin discs and single rear were progressive and still able to lock the wheels up if pushed - how powerful do you want the brakes to be?
I eventually sold it for the same amount I originally paid after 3000 miles when I experienced a very nasty speed wobble and also realising I would have to fork out for more new tyres, brake pads all round and an oil/filter change. I simply couldn't afford to run it and live with its poor handling. If a bike is capable of 150mph, it should be able to go around smooth corners above 80mph without wobbling.
Yes, the steering head bearings were new, lubricated and adjusted correctly; both fork legs had the correct grade and quantity of oil whilst the seals were oil tight; the wheel and swinging arm bearings were in good condition; tyre sizes and pressures were correct; the bike ran true when ridden hands off, and there was no previous crash damage or indications of a cracked, twisted, bent frame. The more people I spoke to the more I'd get the same response - they all do that.
To summarise: Rear tyre 3000 miles; front tyre 4000 miles; brake pads front 5000 miles (guess), rear 8000 (guess); O-ring chain expect 8000 miles plus if well lubricated; fork seals at least once a year; fuel 30 to 50mpg, average 40mpg; top speed around 150mph.
I hope I haven't painted to dull a picture of the Kawasaki. If I had been three or four stones heavier I don't believe the bike would have behaved so badly. Would I have another one? No! Would I have a GPX750 engined motorcycle if it handled well? Definitely if my bank balance could stand it.
For the record, the fastest speed I ever achieved was 135mph (another private road, officer) and the bike was still accelerating strongly. The problem with a fast bike is no matter how sensible you think you are, you will probably use the available power whenever you can on roads which are both unsuitable and have speed limits. I find on my present steed I can have more fun at safer speeds (and its a lot cheaper). Before the suspense overwhelms you, my present bike is an immaculate Yamaha 350LC Powervalve, an H reg with 6000 miles on the clock. This one goes round bends. But as they say, that's another story.
R.Roberts