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Kawasaki GPz 900R Ninja

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Make Model

Kawasaki GPz 900R Ninja / ZX900 Ninja

Year

1986 - 88

Engine

Four stroke, transverse four cylinder, DOHC, 4 valves per cylinder.

Capacity

908 cc / 55.4 cu-in
Bore x Stroke 72.5 x 55 mm
Cooling System Liquid cooled
Compression Ratio 11.0:1

Induction

4x 34mm Keihin CVK34 carburettors

Ignition

Battery ignition, full electronic! 
Starting Electric

Max Power

115 hp / 86 kW @ 9500 rpm

Max Torque

8.7 kgf-m / 63 lb-ft @  8500 rpm rpm

Transmission 

6 Speed 
Final Drive Chain
Frame Iron, Double cradle frame

Front Suspension

39mm Telehydraulic forks air assisted.
Front Wheel Travel 140 mm / 5.5 in

Rear Suspension

Rising rate link-system with single shock, adjustable preload by air pressure, 4-stage rebound-damping
Rear Wheel Travel 115 mm / 4.5 in

Front Brakes

2x 280mm discs 1 piston calipers

Rear Brakes

Single 270mm disc 1 piston caliper

Front Tyre

120/80 V16

Rear Tyre

130/80 V18
Trail 91 mm / 3.5 in
Wheelbase 1425 mm / 56.1 in
Seat Height 760 mm / 29.9 in

Dry Weight 

228 kg /  502 lbs
Wet Weight 257.0 kg / 566.6 lbs

Fuel Capacity 

22 Litres / 5.8 US gal

Consumption Average

40.8 mpg

Standing ¼ Mile  

10.9 sec / 122.4 mph

Top Speed

247.8 km/h / 154 mph

Road Test

Bike Group Test

Cycle Magazine

Motosprint Group Test 1985

Rider Group Test

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THE GPZ900R (ZX900A)

The "Z1", introduced in 1972, astonished the motorcycling world with its engine performance, handling stability, and durability. At the time, its performance capabilities were world -class, earning the Z1 and Kawasaki great respect. Since the later Z1R and Z1000J were developed along the same lines as the Z1, Kawasaki's air-cooled, 4-cylinder, 2-valve engine technology evolved even further and proved extremely popular among motorcyclists. At the same time, however; competitors were rapidly advancing their own technologies. Other manufacturers were undertaking new development efforts to build 4-valve single cylinder engines, V-shaped engines and rotary and turbo technologies, and on and on. Although Kawasaki maintained absolute confidence in its air-cooled, 4-cylinder, 2-valve engines, they had to admit that the appeal of the Z1's technology was beginning to pale. A decision was made, therefore; to develop a brand-new, high-performance, next generation motorcycle by applying everything Kawasaki engineers had learned through their Z1 experiences. This was in September, 1980.

One year passed before a prototype was produced. Amazingly, the engineers had mounted a DOHC air-cooled, 6-cylinder, 2-valve engine to it! Development goals for the new machine were high power output and low vibration and the 6-cylinder smoothly delivered more than 100PS with very little accompanying vibration. For a first-time prototype, its engine layout, impressively, was nearly perfect, but the Kawasaki Engineers were not satisfied. Why? Because the engine was too smooth and, they felt, somewhat tame, especially when their main objective was to develop a motorcycle that would shock the marketplace even than the "Z1" did.


So, they gave up the mild 6-cylinder and dared to build a DOHC, air-cooled, 4-cylinder, 4-valve engine. The decision to drop all of Kawasaki's previous 2-valve engine technology and embark upon development of a completely new 4-valve design, a first for Kawasaki, was based on the need for better charging efficiencies. And with the completely new design, Kawasaki could set motorcycle engineering precedent by adopting a secondary balancer to its new engine to control vibration. For a low center of gravity Kawasaki would, for the first time, adapt its diamond frame technology for a large-displacement, high performance motorcycle.

During the development of the GPZ900R, as with the developments of the MACH III and Z1, the engineers had to leap one technical hurdle after another. One challenge, in particular, was how to effectively deal with the extreme temperatures generated by high-performance, air-cooled engines. The high temperatures produced 'heat fatigue' that caused power output to decline and even warp the valve cover and other vital engine components. Kawasaki engineers quickly found that current air-cooled engine technology would not allow for the development of a durable, high-performance, 120PS air-cooled engine. After all, ten years had already past since the Z1 and its engine technology were introduced.

"A liquid-cooled engine is the answer!" This statement completely changed the development challenges that laid ahead. Research and development efforts were carried out with new resolve and the original development goal of producing something better than the Z1 served to further to the engineers' fervour. Towards the end of 1982, exactly ten years after the introduction of the Z1, the first DOHC liquid-cooled, 4-cylinder, 4-valve prototype was produced. Wet liners were used for improved cylinder cooling efficiency, and the previous center cam-chain was moved to the left side to make the engine more compact. Although the production engine had a single cam-chain driving two camshafts, the prototype was equipped with two cam-chains; one from the left side of the crankshaft to the exhaust side and the other from the right-hand side of the exhaust to the intake camshaft, in an effort to make the cam sprocket as small as possible. By adopting the side cam-chain system, together with the new generator located at the rear of the cylinder, the engineers were able to realize a long-cherished dream of building small engines.

Next came the frame. It was Kawasaki's first attempt to apply diamond frame design technology to a large-displacement, high-performance machine. Because of the diamond frame construction, the engine was considered a stressed member of the frame and had to be included in analysis of the frame's structural integrity. At the time, Kawasaki did not possess the resources necessary for computer analysis so gruelling test-rides of hundreds of kilometers per day had to be carried out, again and again. After various trials, it was decided that high tensile steel pipe would be used for the main frame and aluminium square pipe for the seat rail. An Automatic Variable Damping System (AVDS) equipped 38mm front fork and a rear UNI-TRAK suspension system, together with the 16" front and 18"rear wheels, completed chassis development and provided the GPZ900R with light handling and excellent stability.

With the frame nearing perfection, it was time to delve into fairing design. At a time when 1,000cc motorcycles were the main market forces, Kawasaki was working to topple them with a 900. So of course, the perfect design was required for the "next-generation, Supersports machine." Research was conducted from the dual aspects of great design and aerodynamic efficiency. While maintaining 'good looks', every part had to be produced in a manner that enhanced top speed. Illustrations were based on the slant-nosed appearance of a 'jumping dolphin'-like image. But in the end, the dolphin silhouette had to be toned-down due to market trends that were rejecting anything extreme. Many proposals were made and finally the uniquely modem lines and angular appearance of the GPZ900R were finished. Numerous wind-tunnel tests were made to improve aerodynamic characteristics as well as design quality. The resulting coefficient of drag was a surprisingly low 0.33.

Eleven years after the introduction of the Z1, Kawasaki's newest 900cc could again claim the title "World's Fastest." Its recorded top speed was over 240km/h and its 0-400m acceleration time was 10.976 seconds. After tireless preparation, Kawasaki introduced the new GPZ900R to the public at the 1983 Paris Salon. Its outstanding performance capabilities utterly impressed all who attended the GPZ900R world press introduction at Laguna Seca Raceway, USA in December of the same year. In January 1984, sales of the GPZ900R began world-wide with the word "Ninja" added as a prefix to its name for the North American market. It didn't take long before the GPZ900R became the best-selling bike in the world. It won the title "Bike of the Year" in many countries. Since being introduced 13 years ago, more than 70,000 units have been shipped from Japan despite the GPZ900R having yielded its Kawasaki flagship position to the ZZ-R1100 in 1990.

Bike magazine 1984

Yamaha FJ1100 vs Laverda Jota vs Kawasaki GPz900R vs Honda VF1000F vs BMW K100RS

BMW K100RS

'The easy-going motor doesn't kindle any manic desire to keep up with the pack'

Have you ever felt like a spare tit in the back row of the local cinema? That's what it's like having the BMW K100RS in a hot-shot, rip-snorting, balls-out...ultimate sportster comparison test. Everyone around you is dribbling and drooling and twiddling away at the preload doo-dahs, damping wotsits and air valves, and you're sat there wondering how to get in a quick 200 leagues without arriving back in Douglas after 37 and a bit miles.

Yup, there was a whole lotta gruntin' going on (good grief) but the BMW wasn't going any of it.  Instead, it was more or less whiling away the time until the long ride home when it could settle down to its rather different stride and really down come into its own.

'It's not a sportster,' said Mac, returning the keys after one lap. His tone was that of a man whose lamb has turned out to be mutton. 'But I like it.'  There spoke a man who knew that the man who signed his expenses claims liked the RS too.

We'd met up the night before in Heysham. Mac and Dave, on the FJ and Ninja, looked slightly shagged after a day at Cadwell and a hectic ride trying to get the most from the two multis. I'd come up on the BMW from London, getting a lot of what was on offer, but felt slightly fitter since the RS's best is comparatively further south of the redline.

Arriving on the Island the next morning, we'd watched practice at Quarter Bridge, then gone for the traditional lap before breakfast. Somewhere between Braddan and Ballacraine I realised that, were it not for the fact that Mac was toting a nervous pillion, plus occasional hold-ups from the odd meandering course-learner's tranny, the RS and mo/wouldn't be in the line up come Parliament Square.

It wasn't just that the RS, although faster and tauter compared to its twin pot predecessor, isn't as fast and agile as the three Jap bikes (and neither am I as fast and agile as Brown or McDiarmid), but its long legged comfort and easy-going, slow-rewing motor simply didn't kindle any manic desire to stay with the pack.

That is, of course, the way BMW planned it. In fact, they planned it so well that the Bee Em's main reaction to being expected to hustle like a FJ or GPz is a big Does Not Compute.

Hardly surprising really. Whereas the Laverda, Yamaha and Kawasaki have short, stiffly-sprung suspension at both ends, the BMW has a comparatively whopping 7.3in up front and more average 4.3in at the rear. The springs up front are fairly soft - so soft I forgot about several bumps on my way to work until I borrowed the Ninja.

So if the BMW is braked down hard into a corner in the way the others are designed to do, it goes in with its nose way too low, rear end way too high and waggling on its shaft. The result is undignified in the extreme, although not especially likely to cause anyone to fall off.

The way to do it is to get all your braking over and done with before peeling off, select either of the two appropriate gears (torquey motor), chose round about the right line (some leeway here, though not much) and power through. By this time the Ninja is definitely winning the race, although I calculate that even if it managed the Mountain 20mph faster than the RS (say the Ninja maintains an easy 90mph average), its rider would have just two minutes to get to the bar and buy you a drink.

It wasn't that the BMW wasn't at home on the TT course (it was doing a sight better than the Kawasaki Z1000R went up on last year), but that it and the three Japs were in entirely different ball games. The accent with the FJ, GPz and VF is on high horses.

Explosive powerbands and lightning-quick, taut responses; the BMW is all about a comparatively understressed motor in an over-engineered chassis with the accent on long distance comfort even if it means trading off a measure of scratchability.

Its motor puts out about 90bhp/litre (claimed), while the GPz needs nearly 130/litre to maintain its winning ways, and while none of the other fours could be accused of gutlessness at low rpm, they can't quite match the feel of the RS's slightly undersquare motor as it rolls you smoothly forward from less than 1500rpm in top. The BMW's flat torque curve and relatively compact revband (redlined at 8500rpm) also make early upswaps and all-day 80-110mph riding pleasurable enough to reserve exploration of the last 2000rpm for the enlivening blast to 130mph or more.

The RS has by far the best high speed riding position and protection. Funny how the Japanese went to all that trouble to develop 16in front wheels to reduce steering effort and frontal area on racers and then stuck, ugly great, high, wide bars on their roadsters. Only the Kawasaki has a set of reasonably low bars to take advantage of this.

The RS's narrow bars tuck you down nicely behind the fairing without stretching your body across the tank, while the well-placed footrests put some weight, which'd otherwise rest on your bum, on your legs. The fairing is pretty excellent. Wind and flies still hit your helmet but there's no question of a stiff neck. Aerodynamically, the increased downthrust induced by the fairing and slow steering geometry, make the RS unbelievably stable at speed.

Naturally there's a trade-off in the form of pretty heavy steering at progressive rates, especially since the short bars don't offer much leverage. If you don't like that, sir, may we suggest the K100RT...
The more I rode the RS, the more impressed I became with the purposefulness with which the whole plot was designed. Few riders would fault the suspension unless they were chasing one of the other test bikes; many would welcome its compliance and the need to adjust only a single, three-way preload ring on the rear shock. Aside from its wonderfully clean lines (parked next to the VF it looks like an aeroplane next to a Christmas tree), it also shows much evidence of careful thought; such as the flip switch for quick headlamp adjustment to compensate for a passenger or luggage.

It's not totally insipid or Teutonically dull, however. A secondary vibration period around 3000rpm is occasionally annoying since it buzzes the left footrest at motorway speed in top but hardly rates the added complication of a balancer. The insistent hiss from the fuel pump in the tank has to be lived with, as does a lot of cammy whirring which detracts from the motor's relaxed feel by making it sound as if its turning faster than it is. All the K100's I've ridden have occasionally muffed the first-second upshift, although the clutch is wonderfully light and smooth and gear-changes become quicker and more positive as revs rise.

But the real joke isn't the silencer (which looks like a case of deliberately leaving room for improvement) but the pillion arrangements. What, nograbrail? Words fail me.

With the Jota dying, the only remaining rival to tempt me away from the Bee-Em was the Ninja, mainly because it, too, displays the same singleminded intent and unwillingness to compromise. In fact it's so good it's awesome but since I don't need to go that fast, I can't be bothered to put up with the harshness while riding at under 100mph so I'll be very boring and start saving for the BMW.

Brecon Quaddy

HONDA VF1000F

'All the stuff's there to make one outrageous motorcycle but somewhere in Honda's design shop there's a wet willy'

Just as I was contemplating my notes about the Honda VF1000F and the wet, nightmarish ride I'd had back from Heysham, a photo and caption in one of the weeklies caught my eye. It had pop star Buster Bloodvessel astride some bike at an obscure motorcycle show. The caption went along the lines of 'I like British bikes because they're real machines. I don't like bikes which look like the inside of a fridge.' He meant Jap bikes, of course.

Forgetting all the merits of new technology etc, he had a point. Look at the Honda's instrument panel and you'll see neat gauges surrounded by anti-glare matt black, flanked by the brilliant white of the half-fairing. Everything is so unobtrusive, efficient, clean and functional that, yes, it could be an offshoot of Zanussi. Open the filler cap and, sorry, no a little light doesn't come on...

Looks are subjective though and I'll leave it's all of the 'functional is best' school of thought and the Honda is certainly the most comfortable of the three Jap sports bikes among this collection. It's not as racy as either the Kawasaki or Yamaha, but not as Mr Solid Upright Citizen as the BMW RS. Look at the Honda from any angle and it's taller, slimmer, more 'ordinary' than the Kawasaki or Yamaha. Certainly, when you first sit on it you notice the extra ride height over those two bikes.

The riding position is reflected in its handling, as you'd expect, but only at the very extremes of the performance envelope of these bikes. Back off from those limits just a fraction and the Honda is one helluva good all-round bike. When I was first allocated the Honda to test, I was a bit miffed thinking, as did most of us, that it was a good third in the excitement stakes behind the Kawa and Yam (the Jota had by this time expired, Dellorto Rest Its Cams). I'd ridden the Kawasaki up the IoM via Cadwell Park where I'd watched Mac get left on the line in his classic bike championship race, thus losing the title, and covered half of England at a ferocious rate. How's this overblown 750 gonna compete with that? I thought.

Better that I'd imagined, came the strong reply. Round the Island's bumps the Honda occasionally shook its head a bit wildly. RB claimed it almost threw him off along one lane that he took at 110mph when the rest of us equipped with the power of imagination rode at 80 max. It never got that bad for me.

Then the final piece of evidence came on that ride back. Problems with Jota meant for odd reasons that I finally set out from Heysham at 2am into the slooshing rain, more than a little fatigued and bleary-eyed after three days revelry and bike-biasing. The Honda motored through the buffeting storm, sending out a scorcher of a main beam to pick out the M6 lanes and roadwork cones. It was a shock to cut down to dip beam with its flat topped beam. Take a tip from Cibie, Honda and light up the nearside edge...

After a few stops at service areas, none of which seem to be open on the south bound side at that hour, dawn broke just as I left the motorway and cut across country to Peterborough, my neck of the woods these days. The fatigue etched into my eyes and bones lifted a bit with drying roads and some light and 1 wound up the gas a bit. The Honda's best point came flooding through its motor. Hardly a gearchange was required on the 60 mile-stretch across Northamptonshire, just blast, lean, blast, occasional brake.

The motor is a bored and stroked version of the VF750 rather than a cutdown 1100 V4. It's been achieved with some neat touches: to allow for the wider bores in basically the same alloy block, the steel liners are now pressed in with the coolant running directly against the outside of the liner. This is what's called a 'wet' liner and is similar to the GPz900R. The bore is now 77mm diameter, the stroke increased by 5mm to 53.6mm giving an actual capacity of 998cc. Con-rods, big and small ends have all been strenthenend.

Bigger 36mm Keihin carbs breathe through larger valves, bigger airbox and exhaust pipes. Cams have more lift and duration while the VF750's bugbear - some would say Honda's perennial nightmare - the cam chain has been changed to a straight forward roller chain from the Morse type. Tappet adjustment is by screw-and-locknut. Transmission is much the same as the 750 retaining the odd one-way clutch to help prevent the back wheel locking up when changing gear downwards. The clutch has two extra plates to cope with the extra poke, and the gear ratios altered slightly to take advantage of greater low rev torque. At 100mph the VF1000 is showing 6800rpm.

Oil capacity and the rate at which the coolant is pumped around the mill is upped too, though it's still possible to get the Honda near the read zone in slow town use. In fact, our bike nigh on boiled over at the end of the test but it had developed a small leak from the cover of the waterpump. The VF1000 uses the left lower frame cradle to transfer water to the engine, one of Honda's neat touches.

Chassis is smaller to the 750s, and bears a passing resemblance to the Yamaha's, not considering the FJ's wrap round steering head. It's an advantage being steel rather than alloy, one prang and an alloy frame is usually bent. The engine sits a couple of inches lower in the frame than the VF though it's still higher overall than the others tested here. Nevertheless, it's a fine and easy handling bike with none of the Yamaha's odd characteristics which split the test team almost evenly. At least we all agreed about the VF.

It s the motor which sets the Honda on a pedestal though: power rushes in gloriously at all revs above 4000rpm, and it's no slouch below either. While the Kawasaki requires you to grab a lower cog for sharp overtaking, the Honda will sing away with its distinctive rumbling. Around the TT circuit that's a real plus if you're not as familiar with it as Mac, for instance. Fools rush in but not in the Isle of Man unless they're Roland Brown. The Honda allowed you to go through a corner allowing room to manoeuvre and you could always count on the power response.

The power delivery suits the nature of the suspension and relaxed feel of the riding position. Forks are 41mm diameter with a three-position rebound damping adjuster sat on top of the right leg, while the left leg has twice as much compression damping as the right. Linking the two together is an air assistance system and that rigid fork brace. There's a fair range of adjustment up front and also on the rear Pro-Link shock. For total balls to the hurricane riding round a bumpy circuit such as the TT course, the Honda is a shade soft or at least wallowing but back on normal UK roads these traits are almost impossible to find.

It's bad points are hard to find apart from the front brake. Jumping off the Yamaha or Kawasaki onto the Honda was heart-stopping at first. The Honda's front brake looks trick enough: twin piston calipers with a mechanical anti-dive. But the feel is spongy and lacks bite until you've got the lever some way back to the bar. It works well enough then but is way behind the others in the confidence-inspiring stakes.

The bodywork is well, okay if you fridges. It all fits together well, nothing gets in the way but it lacks the aggressive poise of the Ninja and the practicality of the BMW RS or the Jota. That half fairing knocks a sufficient hole in the wind for 90mph cruising in comfort but this is a bike with 145mph capability.

Over 100mph, it's neck stretch and wrist ache time again folks.
Summing up, I've got to say this is A Typical Honda. All the stuff's there to make one outrageous motorcycle, just as Kawasaki have done with the GPz900R. Corporate responsibility, conscience, no backbone, call it what you like but somewhere in Honda's design dept they've got a wet willy. Shake him out, willya?

Dave Caltierwood

Laverda Jota

'The Laverda makes a wonderful change from the other bikes soulless whirrings'

Remember to take it easy, okay?' I shouted to Mac as he put his helmet on and threw an oversuited leg over the quietly idling Yamaha. He nodded and set off up the ferry's slippery ramp towards land, tail light glimmering brightly through the driving midnight rain. I fiddled with the Laverda's bar-mounted choke lever, thumbed the starter button, gave the motor a few gentle blips and took a deep breath before nosing the ailing Jota into the blackness of the downpour.

For a worrying moment I was left limping at the back of the queue, powerless to keep up if the others suddenly sped off; then Dave dropped back and I was safe. I needn't have worried: a few minutes later, on the outskirts of Heysham, the Laverda suddenly slowed with a death rattle that even Brecon, well ahead on the BMW, heard all too clearly.

We's been planning to call the RAC out from Blackpool but this was terminal and we had no choice.
The Jota was eventually trailered back to Three Cross Motorcycles to find out the full extent of the disaster. A tangled valve had dropped off onto the piston, damaging the barrels, bending a conrod and wrecking the crankshaft. Comprehensively Donald Ducked, to borrow their phrase.

Three Cross couldn't understand it, because the bike had taken 15,000 miles of hard use without complaint before we picked it up. We couldn't understand it either, because the Laverda had begun running badly on almost the first occasion I'd opened it up. The Jota had done no more than stumble round for a couple of painfully slow laps once I'd nursed it to the Island, which was a great shame because if any European machine could have challenged the new breed of Oriental bulletbike then this was surely the one.

The latest Jota model represents the performance pinnacle of Laverda's development of the famous aircooled triples. It takes the later, RGS-style chassis with its bendable Bayflex bodywork and dresses it up with an all-new fibreglass twin headlamp fairing, sensibly cut back now to reveal the beautiful sand-cast engine (early versions of the bike wore a full fairing; both styles are available). The lines are sleek, the colour is a traditional orange and the paint scheme is loud, very loud.

Into that set-up fits one of the later, 120-degree crankshaft engines incorporating, in the case of our bike, a tuning kit that adds £500 to the four-grand price tag of the basic machine. This provides a pair of heavy-breathing 4C cams as fitted to the lovely but short-lived 120 Jota; forged pistons borrowed from the Corsa to give a 10.5:1 compression ratio; a gas-flowed and ported cylinder head and a modified airbox with jets to suit. The raucous black three-into-one racepipe fitted to the testbike is officially not for road use. Three Cross said, but the pipe costs a shade under £200 if you, er, don't ride on the road, know wot I mean, John? It too is loud, very loud indeed.

After the soulless mechanical whirrings of the other four bikes the Laverda makes a wonderful change with its barely-subdued rumble at tickover and its fruity rasp when you blip the throttle. First impressions were good - the bike started easily and felt low, light and manoeuvrable as I left the Three Cross emporium in deepest Dorset and headed along the south coast on the M27.

At a nervous 85-odd mph the Laverda ambled along feeling like a man-eating tiger on a very weak lead.  I had to fight hard to resist giving it a handful of throttle that would probably have been disastrous for my licence, the more so because, annoyingly, the bike had no mirrors and I couldn't read the speedo.

This was calibrated in kph, with illegibly small mph figures inside, and was obscured from my view by the fairing's swept-back screen. At leas that detail is only a problem if you're tall, unlike the awkward twin fuel taps and the horrible only-style Suzuki switchgear. On one occasion I managed the old favourite of blacking all the lights out when trying to use the dipswitch. . .

On the move the bike has that distinctively taut, Italian feel to it - even without the noise you'd have no problem picking it out blindfold. The riding position stretches you out over that big orange tank and the twistgrip has a long action needing a big grab to get the Dellortos fully open and gulping. The hydraulic clutch is still fairly heavy and although the gearchange is positive it has a long travel and needs a forceful foot.

The Brembo brakes are excellent in the dry, almost as good as the Kawasaki's discs, but they're not quite as immediate in the wet at low speeds.
If the Lav was losing time on the Island's straights during its brief blast, then it sure wasn't giving much away in the corners. Not so long ago a front and rear Marzocchi setup was the only way to go if you wanted to get a big bike round the TT course at a respectable rate without bouncing off numerous walls and hedges on the way. And although the Japanese have changed all that and the Laverda's steering is heavy by comparison, you won't find a much more stable perch from which to observe lesser bikes' suspension shortcomings than the narrow black seat (complete with removable tailpiece) of the Jota.

The hefty, non-adjustable Marzocchis up front are just as you'd expect: decidedly firm for everyday use but strong, well-damped and great for attacking the mountain at silly speeds. Rear shocks are remote-reservoir units that seem almost crude by modern standards but which let you know exactly what's going on at the road surface below. With the five-way preload on its minimum setting the ride was well-controlled without being uncomfortably harsh and the Laverda had a reassuringly solid feel in fast bends. Pirelli Phantoms are the normal tyre fitment but our bike was shod with a pair of the new Avon Super Venoms, which gave no nasty moments.

If only its engine had held together the Jota would have been so at home on the Island. The 981cc two-valve triple has to be taken to a heady state of tune to stay in the performance game these days but the rubber-mounted, 120-degree motor remains a beaut. As you wind open the throttle the Jota lurches forward with a bellow, then as the tacho reaches seven grand the exhaust note changes its pitch, the bike leaps onward again and you're heading for the top speed of a shade over 140mph.
Although the motor likes to be revved there's a reasonable amount of midrange power.

The only glitches are fuel consumption that often drops below 30mpg and a dodgy spot at around 2500rpm (apparently that's where the ignition advance comes in) which results in some very erratic behaviour if you try riding along at that speed in town. Apart from that the motor's as flexible and well-mannered as you could hope for from such a fire-breathing old warhorse. If only we'd had more chance to let it show its paces.

Roland Brown

Kawasaki GPz900R

'It was the red and grey Kawasaki that everyone felt happiest on when the going got tough'

The Ninja came out of the open Waterworks right-hander like a rocket, front end hardly twitching as it recrossed the white line while still cranked over they screamed off up the hill. As the tight, walled and straw-baled bends outside Ramsey disappeared in its mirrors to be replaced by the fences, the panoramic views, the fast, often-blind curves and the sheer drops of the mountain the Kawasaki seemed to suck in even more of the warm early-evening air and to puff out its chest with pride. The Ninja was back on home ground: undisputed King of the Mountain.

It was not so much the Kawasaki's sheer speed that got to everyone who rode it, though that was impressive enough. More important is the way the GPz copes with that speed and puts the rider in perfect control at all times. It's single minded to a degree normally seen only in Italian bikes: the riding position is long and low; the suspension is firm and heavily damped; the brakes are phenomenally powerful and it takes six tightly-spaced gears to keep the high-revving motor on the boil at all times. It's a Japanese Jota of a bike, as Dave Calderwood hinted in his test in July's issue, and it makes the FJ1100 and the VF1000F look almost soft by comparison.

Take the riding position, for example. It brings the rider forward to reach the swept-back two-piece handlebars and for pottering round town it's less comfortable than the more upright stance given by the Honda and the Yam. Combined with stiff forks the low, narrow bars give your wrists a tough time and at slow speeds the steering is relatively heavy.

But when you're following a motoring McDiarmid into the Laurel Bank section, peering over the fly-spattered screen as the hedges and walls flash past, frantically trying to remember which way the next bend goes and how tight and bumpy it's going to be, there's just no better pair of handlebars to be holding on to. At speed the Ninja's steering and handling are quite superb if what you thought was lefthander suddenly heads off to the right a slight nudge is all that is needed to put the Kawasaki on a different line, and once it's there it sticks to that line like a 119 horsepower Manx tram to its rails.

In every aspect of fast cornering the GPz900 is precise, stable and confidence-inspiring. Hit a bump at well over a ton on the mountain and the Ninja shakes its head a little, then at once settles down again without any fuss. On one incredibly bumpy stretch off road going towards Jurby Airfield the Honda got into a nasty high-speed tankslapper (the only time I got it to misbehave seriously, I should add); when I went back over the same bit of road on the Kawasaki its bars got very lively but there was no need to slow down. It's a shame the Yamaha wasn't on form, it might have run the Ninja close, but it was the red and grey Kawasaki that everyone felt happiest on when the going got tough.

Another reason tor that were the brakes, which are as good as any I can remember using. The front discs are incredibly powerful, needing only light pressure on the lever, as well as being very progressive and controllable. The Kawasaki has little of the FJ11's tendency to stand up when braking into bends, and with its powerful AVDS anti-dive system the Ninja retains a wonderfully stable front end to encourage you to squeal the front Japlop right into corners.

There's a fair bit of jarring through the bars whichever of its three positions the anti-dive is set on, and the same goes for the fork air pressure. Recommended settings vary between 5psi and ail of 8psi; I preferred the higher limit and was happier with the 21psi maximum in the rear shock and the four-way damping turned up, which helped when it came to carrying a passenger. Like the older GPzs' the Ninja's shock adjustment is a screwdriver turn away, behind a sidepanel, so altering settings is a time-consuming business.

When you're riding the Kawasaki it's hard to believe that its 908cc motor is giving away a significant number of cubes to all its competitors. The watercooled four-valver lacks the midrange punch of some, true, but it's a great engine: silky, narrow and very, very powerful. Keep it above 6000rpm and the Ninja responds instantly to the throttle, and even below that figure it runs cleanly and is noticeably less peaky than the most recent two-valve GPz1100 motors.

It's also very smooth, thanks largely to the gear-driven balancer shaft situated directly beneath the crank. This turns backwards at twice crankshaft speed and neutralises the engine's tingling secondary vibration, which in turn allows the power unit to be solidly mounted and to act as a stressed member of the skinny-looking but obviously immensely strong frame. Very little vibration gets through to the rider, even when you make use of the real megapower lying between eight grand and the 10,500rpm redline.

That sort of power band means plenty of hoofing around through the thoughtfully provided six-speed gearbox but even when barrelling round the Island's ribbon of blind bends I rarely found cog-swapping a problem. Like the rest of the bike the Ninja's gear change seems to work best when the going is fast round town, changes tend to be clonky but at high revs you can flick up and down instantly and the lever action is so sweet you need hardly give it a thought. Only dodgy part of the transmission is the clutch - our original testbike's unit gave up completely at MIRA and the second bike's clutch was obviously poorly after just a few gentle half-mile runs. One slow, juddering and shrieking launch produced a best-ever (wind-assisted) 11.13 second quarter so I packed up and went home while the going was good.

There were a few other niggles: a slight oil weep from the camchain tensioner region (the Hy-Vo camchain runs up the left side of the motor; the alternator sits behind the engine and is chain-driven from the right of the crank); a leak that meant the coolant tank had to be topped up on a few occasions; and the failure of the temperature gauge on the last day of the test. More general faults were mostly related to ergonomics. The fairing provides no hand protection and its mirrors are too close together; the indicator switch is basic and the dipswitch is small. On the plus side the grabrail is strong and the retractable bungee hooks make luggage carrying easy unless you're two-up (which is often when you most need it, of course).

It would hardly be stretching a point to say that on a bike such as this we should be grateful for any concessions to practicality we're given, after all the Jota has no mirrors at all. But when the opposition is as hot as the Ninja's is Kawasaki can't afford to slip up on even the slightest detail. For superquick roadwork the Yamaha, especially, is so close behind that it's the rider who'll make either bike the quicker over most twisty roads, and the FJ1100's extra midrange, greater comfort and better detail work tempt me to pick it as my favourite. Then I remember my last, fast Island lap on the Ninja - the uncanny stability as it banked through the Bungalow, the awesome speed as it flew down the hill towards the Creg. And once again I'm not so sure...

Roland Brown

Yamaha FJ1100

'Mean looking and low, the Yamaha offers promise and delivers - in spades'

Get one of these and you'd better recalibrate your diary. It took at least a week's custody of the FJ1100 before I got the hang of not arriving for appointments half-a-county away at least a pint ahead of schedule: you just aim in the general direction of your destination and delight in getting obviously lost, secure in the knowledge that the Yamaha will get you from anywhere to almost anywhere else in less time than you've got.

And about time, too. Until now Yamaha's range of big four-strokes has brought them to the verge of financial collapse and the rest of us adrenalin cold turkey, particularly those allergic to mainlining on two-strokes. Their range lacked overall pzazz and a flagship in particular: the FJ is both and right up there with the best.

Mean-looking and low, the 1100 offers a promise and delivers in spades. The compact four-valve, twin-cam motor pulls smoothly in any gear from 1500rpm, then starts to burn serious rubber from 6000 to the redline at 9500rpm. Although peak torque arrives as late as 8000rpm, the mill, puts out above a healthy 50 foot-pounds all the way from 3500rpm to the redline; for comparison a Ducati 900SS peaks close to that figure. Coupled with impeccably clean carburation and instant throttle response, this makes for gusty acceleration at practically any revs in any gear. Equally crucial, the power band is progressive and predicable.

Compared with the GPz and VF, the FJ has appreciably more mid-range than the Kawasaki, less sheer bottom-end but marginally better extreme top-end than the Honda. In a top gear roll-on from 70mph against that all-time king of grunt, the Yamaha XS11, the FJ initially lost 20 yards or so before resoundingly clearing off above 110mph; stir those slick gears a little and the XS might as well be a pony trap. Without the pony.

Considering the amount of stomp on tap the FJ is commendably frugal, averaging 42.9mpg overall. The low of 37.3 was guzzled two-up with luggage on fast A-roads, arriving dead on time after a mileage under-estimated by 50 per cent; the high of 52.9 was at night on unfamiliar B-roads into a blizzard of midges, but otherwise without especial restraint. Full-tank range is upwards of 180 miles, the reliable fuel warning light coming on about 20 before this. There is no reserve and the fuel gauge is a waste of space.

The FJ is equally civilised off the forecourt. Mechanical noise is limited to muted valve-train chatter and transmission whine. That, eerily, is all there is to be heard on the overrun. The exhaust is all but inaudible. Even after the most brutal caning the tickover settles to a steady whirr, and the motor fires on the button cold, hot or very hot. Astonishing, when you consider that this sort of specific power was close to the limit of technical development only 20 years ago.

But if the FJ didn't handle on a par with all this magnificent clout, you could stick it in your ear. Fortunately it does. Despite a temptation to dismiss the 'lateral concept' frame as so much Jap speak, it appears as rigid as any more conventional cradle; also offering exceptional maintenance access and looking trick into the bargain. The bike steers with real precision at all speeds, save with a slight tendency towards understeer on slow corners where really huge bumps can also make it sit up.

Yamaha has made the most of 16-inch front wheel technology (the similar diameter rear is neither here nor there, and is anyway so fat-tyred as to have a 'conventional' rolling radius): there are 18-inchers which steer as quickly, but at the price of highspeed instability. The quick steering characteristics of the small wheel have allowed Yamaha to employ lazy steering geometry at the yoke offset, for instance, is distinctly Ducati's without the pentalty of advance application, in writing, for direction changes. In addition the designers went to considerable trouble to keep the engine as short as a typical 650cc transverse four; the resulting short wheelbase also contributes to responsive steering: the FJ is nearly three inches shorter than other Japanese 1100s.

For its size the FJ changes line rapidly and with a minimum of rider input, impressively so at very high speeds. It readily chops line on corners where lesser bikes are committed to one and accepts quite heavy front brake deep into turns. Overall it's rather less agile than the lighter but equally solid GPz and slightly slower steering but more stable than the VF. All three, though, bring a new dimension into the combination of power with handling.

Unfortunately some of the FJ's precision goes out to lunch as the original-equipment rear boot gets clapped. Grippy these Japlops may be, but they become increasingly prone to white-lining and high-speed weave. To put this in perspective it never became remotely alarming or occurred within hailing distance of UK speed limits; it's just there.

This tendency could be dialled out in part by upping rear suspension settings and completely vanishes with new rubber. It's probably worth experimenting with the various alternative tyres available: one reliable source claims Pirelli Phantoms are the answer.

Suspension both ends is multi-adjustable for damping and preload, although the correct alien key for the forks would be a welcome addition to the tool kit. (Not everyone has a GPz on hand for this purpose.) Ride is supple and compliant even on the hardest settings, although to my mind the monoshock is both slightly under-damped and under-sprung. The forks are substantially braced and with the anti-dive set close to minimum I couldn't fault their action.

The brakes are superb, powerful, progressive and full of feedback. Although they give slight best to the Kawasaki, they're light years ahead of the Honda's, which faded with surprising ease. Early anti-dive Yams had a sponginess from pumping up the fork hydraulics, but the FJ has no such problem. Leverage ratios at the rear are ideal: even the clumsiest boot, of which I have two, is unlikely to lock the wheel.

Grounding anything but the fold-up footpegs is strictly for nutters and heroes, who'll probably also want to ditch the centre-stand which scrapes under extreme duress. Said citizens will also appreciate the TV-size mirrors to admire their trails of sparks, and incidentally to keep an eye on the Old Bill. All they're likely to find behind that slippery fairing, if they ever catch you, is a grin. The rest of your development will already have been arrested.

Mac McDiarmid

CONCLUSION

With the notable exception of the Honda, all five bikes lived up to expectations. The most expensive is the BMW at £4495 doesn't offer the performance and handling brilliance of the cheapest bike the GPz900R at £3199,  but justifies its high price in terms of equipment, finish, reliability and remarkable long distance comfort.

The Laverda, at £3999 basic (£500 more with the tuning bits), comes closer to the Japanese bikes' performance but depends largely on subjective appeal and its Italian heritage. Apart from the RGS Corsa, it's the best non-Japanese musclebike around.  Making a choice between the three Japanese machines promised to be harder than deciding whether to buy a BMW or a Laverda.

All offer more poke than anyone seriously needs, excellent handling, and price tags to make European sales directors weep. In the end it was lack of startling virtues, rather than any major vices, which relegated the VF1000F to third place. It was just too. . . nice. The FJ1100 looked at first to be a big threat to the Ninja, with more power and greater potential as an ultra quick tourer.

Ultimately, however, everyone voted for the Kawasaki. Over £300 cheaper than the Honda or Yam, it equals or betters both as a street racer, has superb brakes, and always feels more exciting. Which is surely what a sports motorcycle is all about. If it wasn't for the BMW and Laverda, picking the Ninja as overall winner would be easy. But few could dispute the K100RS's ability to live up to its maker's promise. Nor is the Jota the worse off for Laverda's refusal to totally sanitise their products: quite the opposite. All three are winners, although if you've always reckoned that cheapest is best, Kawasaki have proved that the best, for once, is also the cheapest