Another feature of the engine was the balancer-shaft, novel for a four in '84, that allowed the unusually smooth power unit to be employed as a stressed member of the chassis. The frame combines a steel backbone with an alloy rear subframe. Unlike Triumph's recently-launched backbone frame, the Kawasaki has three narrow top members instead of a single thick one. But you can bet that the Hinckley engineers, whose plans were starting to take shape in '84, we're influenced by the Ninja's design.

The most important changes to the Kawa are elsewhere on its chassis, most notably the front wheel that grew from 16 to 17inches in diameter last year. At the same time both wheels were widened by half-an-inch, allowing a fatter 150-section bias-belted Dunlop to be crowbarred onto the 18inch rear. And the 38mm front forks grew to 41mm in thickness, shedding their hydraulic anti-dive system - like the 16incher, as dated an '80s style statement as red braces and shoulder-pads - along the way.

Brakes were changed, too. The front discs grew to 300mm in diameter, semi-floating rather than solidly fixed (to help pad alignment) and grasped by heftier four-pot Tokico calipers. The rear disc was reduced in diameter to 250mm but received a twin-pot caliper of its own to make amends and keep the pedal in a job.

Brake and clutch levers were binned to make way for four-way adjustable replacements, and a variety of other details were likewise replaced by bits from other models. Clocks come from the ZX-10, handlebar grips from the ZXR750, push-to-cancel switchgear from the ZZ-R600 and mirrors from the 1000RX. This year's only change is a new one-piece handlebar, apparently deemed necessary because the old design occasionally made a worrying (though not dangerous) creaking noise.

It's a wonder the whole bike doesn't creak when you fire it up, for the 900R has been in Kawasaki's range for so long that it has outlasted not only its supposed replacement the 1000RX but also the more recent ZX-10. It sounds the same as ever, of course, whirring and whining and taking a fair time to warm-up. By big-bike standards the Ninja was a very compact machine when it was launched, and it still feels reasonably low and well-balanced now. It's actually slightly longer, heavier (at 5151b dry) and taller than the ZZ-R11, so perhaps it was a relative lack of bulky bodywork that made the lithe-looking 900 seem the smaller bike of the two.

The above list of detail changes is short, so I was surprised to find the mutant Ninja (soon it'll be a teenage mutant Ninja, if not quite a turtle) feeling noticeably different from the old. You'd have to run them back-to-back to be sure, but the new bike's front end felt a little more laid-back and slower-steering than I recall the 16incher. Rake and trail figures of 29 degrees and 118mm are about as close to the sporting norm as Freddie Spencer's collar size, but no complaints there because the Kawa's neutral feel suits its slip into sports-tourer mode just fine. (Perhaps Freddie should try entering the National Rally?)

The anti-diveless forks worked pretty well, too, giving a reasonably firm ride without approaching the taut feel of the big ZZ-R. I was always pretty keen on the way the anti-dive firmed things up when you hit the brakes hard but, in combination with the Ninja's fairly stretched-forward riding position, that set-up was decidedly harsh on the wrists. The newer front end provides greater comfort at the expense of more fork-dive under braking; meanwhile the unchanged, air-assisted rear soaks up the bumps as nonchalantly as ever.

The anchors also proved very adequate, though surprisingly they felt less powerful than the original bike's combination of smaller discs and stone-age single-pot calipers. If anything the old set-up was a bit grabby, and a few riders have gone for a slide up the road after taking too big a handful. The newer set-up is more progressive, but with eight pistons to call on I'd expected a bit more bite from the front stopper. Perhaps it's just a sign of how good the opposition now is.

The engine suffers from such comparisons in the same way. Back in '84, of course, it was the ultimate rip-snorter. In that year my proddy-race GSX1100 was brim-full of illegal Yoshimura gear, yet the bloody bog-stock Ninjas still came steaming past before the end of the Snetterton straight. These days a ZZ-R would leave the 900 for dead and Suzuki's GSX-R1100, 501b lighter as well as 10 horses more powerful, would make it look positively sluggish round Snetterton.

And it's no good kidding yourself that the 900 can hide its age so long as you keep away from a racetrack. The Kawa still storms to warp speed in moments - its rejigged tacho and speedo needles dancing round their dials with as much enthusiasm as their predecessors - when you keep the motor on the boil with the sweet-changing six-speed gearbox. It still tops a genuine 150mph, and it still demolishes the quarter-mile in a shade over 11 seconds.

But the old-style power step at around 7000rpm seems more obvious now that so many big bikes have more beef in the midrange. And the traditional Kawasaki hole below four grand, much improved on the ZZ-R, now intrudes where in the old days you were having too much fun to notice it. There's more vibration than I remember, too. Nothing annoying, but a distinct tingle through seat and pegs above the six-thou mark, corresponding to around lOOmph in top gear.

Even so, on a motorway you could cruise comfortably at that speed until blue lights interrupted your progress. The slightly narrow-looking fairing and seat are impressively efficient, there's plenty of room for both pilot and pillion, and the fuel tank takes a reasonably generous 4.8 gallons. Just load up, point it and go: the Ninja comes with as well-proven a reliability record as any bike and with more performance than all but a few.

It won't turn many heads, it won't make you want to rush out and ogle its engineering, and it might not always inspire you to take it for a thrash just for the hell of it. But the GPZ900R will provide easy speed, vice-free handling and plenty of comfort, plus that all-important bonus of cash in your pocket that you won't get with something equally good and more modern. In impoverished times like these, that combination is enough to make Kawasaki's well-preserved old warrior well worth a serious look