There are lots of fast bikes available in the used motorcycle marketplace but I was really pleased to buy a 9000 mile, two year old GPz500 for £2000. I'd tested it by pulling a wheelie in first gear. Not an easy task as it needed a wicked wrench on the bars and throttle. The bike’s balance wasn’t perfect with an urge to throw itself sideways into the gutter.
The engine made all its serious power between 7000 and 11000 revs, tried to trash the drive chain at the bottom end of the rev range. The six speeds worked with all the fluidity of a Ural but invariably engaged. The downwards change through the box was much smoother than the upwards. The OE O-ring chain was about half worn, careful adjustment determining the transmission’s exactness.
These were my early impressions, confirmed by a fast thrash up one side and down the other of this great country of ours. I just did the run for kicks, none of that charity shit. Top speed was an indicated 130mph, the motor feeling busy rather than vibratory. The half fairing was quite efficient, judged on the way the bike surged forwards between the ton and ton twenty.
Fitted with Japlop shod sixteen inch wheels, high speed stability was better than expected. Felt well planted to the tarmac even when flat out. Later bikes had seventeen inchers, running fatter tyres - the one drawback of the smaller front wheel was that it could suddenly let loose in bends, usually when the tarmac was less than perfect. I didn't experience that suicidal move, mostly because I looked where I was going. I did note that the bars shook when accelerating hard out of bends with just slightly bumpy surfaces.
One good aspect of the small wheels was that the 400Ib twin was easy to chuck through the bends, feeling more like a 250 than a full blown 500. I tried both Avon radials and Michelin tyres, but could discern little difference between the various makes and the Japlops worked out as the cheaper option (rear 6000 miles, front 8000 miles). One reason it was difficult to tell the difference between the brands of tyres was that the bike felt a touch remote from the road, lacking that essential communion between machine and tarmac. It wasn’t the kind of motorcycle that you could take right to the edge and hope to survive to tell the tale.
The poor quality suspension’s undoubtedly to blame for the remoteness. Even when I bought the bike at its relatively low mileage, the spindly front forks would clang and clatter over rough going. The rear shock, served by a Uni-trak arrangement, felt harsh and soft at the same time. The ride was still quite plush, doing a good job at absorbing most bumps, and when upright or banked over on smooth roads there wasn’t much to complain about. When bumpy bends were involved, a hinged in the middle feel predominated and it didn't take much effort to get the chassis all crossed up.
In its favour, the chassis was neutral, didn’t go berserk if the brakes were gently applied or the throttle slammed shut in corners. It was also light enough to haul on to a different line when necessary or pick back up when I wanted to make a straight line out of a corner. In short, the square section frame was up to the job of keeping the quick wear suspension in line.
It didn’t take long for the contrast between the hard charging engine and squeamish chassis to irritate the hell out of me. This coincided with a buxom lass being taken pillion, her weight making the back tyre rub through the plastic mudguard. The single front disc was also troublesome, the pads rattling around like they were down to the metal and the whole front end squeaking during low speed stops.
It didn’t take a great intellect to work out that a stronger shock and whole new front end were needed. Stuff off a GPz900 was bodged on, giving the bike a solid feel, more Ducati than Kawasaki. The twin discs almost had me over the bars the first time I used them in anger. The only downside was a bit of a handlebar flutter at 115mph. I found that I could ride through it, the bike feeling much safer at 125mph! Any excuse to speed. As if any was needed!
The GPz was a relaxed 90 to 100mph cruiser. Plenty of protection from the half fairing, a useful surge of acceleration in hand to see off any erring cagers, and rock-like stability with the upgraded suspension. With about 40mpg I could survive for 180 miles before worrying over fuel, which was about right with regards to comfort. The ergonomics were spot on but the seat needed an extra inch or two of padding as a hundred miles had me squirming around a little whilst 300 miles in a day resulted in a funny walk.
Wet weather wasn’t much fun. My gloves were quickly soaked through and the minimal mudguarding, especially at the front, left the whole chassis in a far from pleasant coating of grime. The black engine make-up and tank paint were the best aspects of the finish; every screw on the bike was soon speckled in rust, the exhaust was quick rotting and the silver frame was seeping corrosion from underneath its paint. The alloy wheels corroded rapidly, as did the stands and handlebars.
The plastic was strong and flexible enough to survive the times the bike fell off the wimpy sidestand - usually, the indicators exploded. The fairing was susceptible to stones flying through the air and the excellent headlamp was holed by one stone but continued to work with searchlight intensity One thing to watch for with the electrics is that the battery can lose half its water after a hard day’s 500 mile thrash.
One thing that caught me out was the time a spark plug burnt out. The engine wasn't impressive as a 250cc single... I tried to do a roadside repair because I had a spare set of plugs, having read that they don’t last for more than 5000 miles. You wouldn't believe the hassle I had just removing the petrol tank, someone seemed to have glued the fuel pipe on to the tap. The plugs are a long way down in the cylinder head and I almost cross-threaded them! Not funny, some of these companies have given up on the real world of roadside repairs.
Once access was gained, the GPz was easy enough to maintain. Adjust the eight valves every 10000 miles and balance the carbs at half that distance. Even the air filter could be cleaned out with an air-hose. Oil was changed every 2500 miles and the oil filter whenever I felt guilty about it. An excess of slow town work caused the sight glass to sludge up with white gunge from condensation in the oil but a hard blast cleaned it up. I prefer a dipstick myself as they are less dependent on putting the bike on a perfectly level surface.
I did about 35000 miles in eighteen months with no major mechanical hassles. The motors, despite developing 60 horses and liking to be revved, are known to be tough, with the cam chain the first thing to go at around 50000 miles (maybe half that if regular oil changes are neglected when the cam lobes will also scar). The major sign of wear is in the gearchange and looseness in the final drive chain (curiously, and primitively, primary drive’s by hyvoid chain and not gears, but it lasts well). It's never as bad as some Hondas, but it does show up an otherwise sophisticated piece of engineering; at least until you get used to its machinations and learn to ride around it. One less gear would happily be exchanged for a slicker box. If, on a test ride, you find the gearbox completely impossible then it’s probably a sign of very high mileage.
GPz500s do attract the hard cases and it’s also an ideal DR mount, making it difficult to find nice ones, especially with the way the finish goes off rapidly. I managed to sell mine for £1750 and buy a nearly new one for £2700 (the better suspension and wheels making post 94 bikes somewhat superior) with just 2400 miles on the clock. This one’s really immaculate and I intend to keep it that way for the next two or three years (helped along by the excellent Scientific Coating’s liquid on the chassis).
The GPz carries on the fine tradition started by the Bonnie, bikes that are very versatile, fun to ride and not so expensive to run that you have to rob banks.
Peter Daller