Kawa GPZ500S: Bargain Brainer

The red GPZ500S was cheap, 750 notes. The clock read 76000 miles. The cosmetics were crap - alloy rot, rust, and leaking suspension and engine. The motor rattled into life with its off-beat note, spewed out a bit of oil and then settled down to a 1200rpm tickover. I swung a leg over the elderly beast. The bike fitted me to perfection, felt immediately at home with the GPZ. Until the thing leapt forwards a foot with engagement of first gear. Clutch drag from cold! The box had engaged as if the selector's dogs were well shagged.

First ride. Weak, imprecise front end. Bouncing rear. Horrible gearchange, loads of chain lash. The single front disc was still strong. The engine growled fiercely at 7000 revs and shot the bike forwards. Not hard enough to do my vision in but I smiled nevertheless. The 375lb machine was easy enough to point where I wanted despite the shot suspension and infamous sixteen inch front wheel.

I offered 650 notes, the bike was mine for 700. Riding home, I played with the throttle, struggled with the gearbox and fought with the handlebars. I won out, arrived back at HQ with a big grin if shaking hands... the vertical twin motor has its pistons moving up and down alternatively and a gear driven balancer, but wear had got to the components, vibes pouring out, especially between 3000 and 6000 revs.

Nothing I couldn't get used to, having spent a pleasant couple of summers with a GPz305 - you want to experience vibration, mate, ride a 305 with shot big-ends! The GPZ500 could still put 125mph on the clock without any real effort on the part of the motor. The chassis was a different ballgame, the suspension being completely worn out! The tyres were marginal Avon radials. The bike didn't so much hold a line as hop from bump to bump, white-line to white-line, like a high speed rabbit looking for somewhere to die. Fighting the bars tended to blow up the weave into a wobble, much better to gently caress the grips and go with the flow, as long as the flow was going where you wanted to go...

The first time I got into serious trouble, I'd over-cooked my line into a bend where some old git was meandering along on the other side of the road where the GPZ wanted to hustle. The suspension had already bottomed out and gone into a self destructive frenzy due to the complete absence of damping. Applying the brakes turned the bike into a rigid framed horror that bounced to the left and then the right, gave every impression that it wanted to throw me out of the seat. Holding on to the bastard and leaning off to one side persuaded it that it wouldn't be a good idea to smash into the oncoming vehicle.

My survival was accompanied by a sudden need to dump the contents of my bowels, a rank smell of fear coursing off my body. After five minutes recovery, I kicked the tyres, shook the forks and patted the tank. The latter gave with frightening ease, no doubt rusting away from the inside out. The rest of the ride home was done at a much more moderate velocity, the lack of revs showing up various engine rattles, massive driveline lash and a disturbing need to fall into corners.

The long list of bits needed added up to more than the cost of the bike, so the obvious hunt through various breakers was undertaken. My requests for a newish front end were greeted with hilarity - GPZ's notorious for losing it from the front, mashing the weak forks. Nothing for it but to strip the forks down and bung in some new seals and stiffer springs (they were weak from new!). That cost forty notes, grazed knuckles and general disillusionment with the build quality of Japanese motorcycles. The caliper's bleed nipple, for instance, needing to be drilled out and the replacement Araldited back in (not a good idea - Ed!). A used shock off some huge old bruiser of a four was persuaded on, new swinging arm and headstock bearings further reducing the chassis slack.

Even more dosh was spent on a replacement petrol tank, sprockets and chain, newish saddle, a battery that didn't have white plates and new cables all round. All that added up to a wonderful firmness, good directional stability and a useful flickability. The driveline still whirled around in a frenzy below 3000rpm in any gear taller than fourth and the motor still put out an excess of vibration, but I could now ride the bike between 7000 and 10,000rpm without fear of hitting cars or ending up in a ditch - those revs held all the power and allowed the engine to smooth out to an acceptable degree, though I would never describe it as electric.

The major problem over the next 4000 miles was the finish. I spent a whole week polishing the beast up to a nice shine, cleaning off the rust and patching it up, and also getting all the crud off the alloy. All it took was a couple of days of rain to have it going back to nature pronto. The silencers were evidently original, a major achievement given the mileage. The price paid were large areas of rust, little baffling left and the need to hustle along in a tall gear whilst in town; otherwise the rozzers went absolutely berserk. I reckoned that the silencers had about a month's life left in them!

A Motad 2-1 was hammered on, not new as they are too expensive. This f..ked up the carburation something rotten until I took out the ancient air-filter for cleaning - they can be done by blowing air through them, so at least that was cheap enough. There was still a bit of a stutter between 4000 and 5000rpm but it was easy enough to howl through with a bit of thought and effort.

The only way to deal with the rotting chassis parts was by replacement. Even the plastic was going off, cracking around the mounting holes and sort of fading away to a horrible shade of white or red. The engine finish was intractable, could be cleaned up but the white fur came back rapidly. Rust seeped from under the silver frame paint without actually making it fall off! It cleaned up but kept coming back. Skimpy mudguards didn't help. Having no faith in the state of the engine, I wasn't inclined to rip the bike down to its component parts, blast 'em and powder coat.

After 4000 miles I realised that something was seriously amiss with the engine. Starting was difficult, power was misery and vibes increased to worrying levels. I decided it needed an oil and spark plug change. The former was a piece of cake, the latter a disaster. Appallingly, the plugs need the petrol tank removed and are located deeply in the cylinder head. I was pissed at all the effort needed to replaced them and went completely ape when I stripped the right-hand plug thread! Only an excessive amount of willpower stopped me using my largest hammer on the engine!

An interesting horror story was revealed when I started stripping the motor down. For a start, the engine bolts were seized in solidly, needed an excess of hammer work to get them out. Every thread in the engine seemed seized in as well. When I finally got the cylinder head cover off, the camshaft lobes and rockers were shot to hell and back again. By the time I'd removed the head, I wasn't that surprised to see scored bores. Worse still, the small-ends were loose! Given the awful state of the gearbox there wasn't much point trying to rebuild it.

A newer engine was installed, much smoother and more powerful yet. The chassis was trying hard to return to dust, so a quick polish and trade-in deal at the local importer got me some wilder wheels.

H.R.