During the early 80’s the world sat around awaiting the next big thing in motorcycling. Big capacity, air-cooled, muscle bikes had become the norm and most expected this march to gain momentum, few however expected Kawasaki’s next move and the result changed the face of the Superbike forever.
There isnt many times when a dated Japanese design from the early 80’s is put back into production, the Nippon way is usually new must be better, simply because it has been developed further and yet Kawasaki did just that in 1990 when a six year old design suddenly appeared in the UK sales brochure. There is a reason why the GPz900R, or Ninja as it became known in some markets around the world, was reintroduced into the Kawasaki range in this way. This wasn’t just a knee-jerk reaction from a manufacturer with little else to offer as the range had moved on many times since the GPz900R had first turned a wheel, the staggering ZZR1100 was just around the corner while the ZX10 was already doing sterling work. This benchmark 80’s superbike still had a huge fan base with demand for something a little different to the plastic rockets of the 90’s still strong.
This agile and grunty liquid-cooled four still had the legs to hold it own in straight line and was never too lardy in the twisties either. Add a seating position that doesn’t load the wrists, or cause backache, within minutes and the Kwak could be called upon as a half decent VFR substitute. To get what the GPz is all about however one must sample an early version, only then does the genius of the design become apparent, there are a few references to what had passed before it but, these are of little significance, this machine is all about each and every component working for its living. There are no free rides on this bus and all must chip in, making the sum greater than the parts ever could be. With this thinking working to great effect the GPz went on to dominate production racing for the first few seasons following its introduction, racers soon finding the bike to be near perfect straight out of the box particularly for the lengthy TT races, GPz’s taking the first three places, along with new lap and race records, in the 1984 production race.
The engine is a lesson in how to mix new and old thinking, creating a strong and trustworthy power plant capable of taking the next generation of Kawasaki Superbike well into the 90’s and beyond, traces of the original GPz being found, still going strong, in the ZZR series many years after the launch of the original. despite its simplicity the chassis is staggeringly effective too, its basic steel tube construction and, on paper at least, lazy steering angles, conspire to create a rock steady ride especially when at heady speeds. Everything just works well, from the feeble looking, but high performing, twin disc set up on the front end to the skinny wheels and tyres that never fail to provide the grip you ned to humble many a power range on his modern rocket ship.
At the end of the day the GPz can be looked on in many ways, it is a desirable classic, and yet with a look that clearly means business, it is also a reliable machine capable of day to day commuting, that dependable engine and superbly put together, taught chassis giving a fun filled and speedy ride. It is also a design icon, instantly recognisable as a ground breaking machine with few whistles and bells that usually accompany such an event, to put it simply, it is still a great among a sea of pretenders and imitators.
Living with a Ninja
To put this machine in context one really must have sampled, or at least have some considerable respect, for those brutish muscle machines that came before it, machines like the GPz1100 or Suzuki GSX1100, the biking equivalents of a hammer to crack a humble walnut, only then can you see and feel why the world was knocked for six by the 900R. These huge powerhouse machines rocked the planet with a heady mix of horsepower and debatable handling whereas the GPz900R worked hard to be near perfect in all areas by using altogether different approaches to the same task. The compact engine makes up a large proportion of the frame work, acting as a stressed member while cleverly designed suspension keeps the machine in perfect order at high speeds and steep angles of lean. This is at the expense of some harshness felt at lower speeds with pot holes and other modern day road unevenness making their presence upon your spine but this isn’t for long and, once the road opens out the bike becomes smooth and riding it, effortless. At speed, the fairing also comes into its own, lessons learned with their successful Grand Prix race machines of the 70’s were implemented on the road too great effect, clever use of this knowledge in the wind tunnel resulted in the most slippery road going Kwak to date.
Low down power and torque isn’t so impressive, requiring a deft use of the slick six-speed gearbox to keep the bike buzzing, it does kick in positively around 5000rpm and gets stronger as the revs rise until it peaks just short of the maximum horsepower. This characteristic makes for an exciting ride when the full extent of the engine is used, fuelled smoothly, and accurately, by a bank of Keihin CV carbs there is not a glitch to be found at any point in the tacho needles arc.
If its classic looks, head turning ability and practical, modern usability you yearn for then there can be few machines from the 80’s quite like the GPz900R. With the exception of a few scarce original parts like the fragile mild steel exhaust silencers, running a GPz shouldn’t be a difficult task. There is a healthy presence of owners clubs and other such fraternal help, along with a good supply of parts and knowledge enabling this classic to be viewed as a practical alternative to a modern machine, later models are cheaply available too wit many post 96 versions finding their way into the UK market as grey imports.
If any machine can lay claim to being present at the birth of the modern Superbike then this Kwak is it, setting the standards in engine and chassis design that, with a few early 80’s foibles apart like anti dive and 16-inch front wheels, would still be around, and much copied, many years later.
Kawasaki GPz900R Model history
Just when the biking community thought they had it sorted, the world of big capacity air-cooled fours was shot to pieces, and Kawasaki regained the crown as the manufacturer of the best and fastest, with the GPz900. It was light, powerful, albeit less so than the 1100cc machinery it replaced, and lithe too making the new 900 the benchmark for others to beat. It also set the stall out for a number of features like liquid cooling and full fairings that would become the norm. There was also a little something that wasn’t so apparent when looking at the spec sheets and pr blurb, this was a big bike that felt like a small one, as easy to throw around as the best of the 750’s, while stomping as hard and as fast as the old school Superbike. To achieve this Kawasaki had turned a back on the last ten years of development, a period during which they had produced some of the best four-cylinder machines of the decade and designed an all new power plant. It nearly didn’t come to fruition however as early prototypes, built when the project started in 1980, went down the wrong route with over complex six-cylinder engines and much innovation simply for innovations sake, thankfully the light was seen and the machine shaved down to produce the stunning slim and fast machine we know today.
Its engine a breath of fresh air that influenced all that followed, significantly, the cam chain was moved over to the far left of the engine, in doing so making for a narrower four-cylinder layout than with the timing chain running up the centre, keeping the lower end of the engine as slim as possible for maximum lean angles and small frontal area to reduce drag. The design lived on, making it arguably the longest production run of any large capacity machine, and actually outliving many of the later machines it spawned, the GPz1000RX and the stunning ZX10 all came and went. The GPz900R remained in production for nearly two decades, finally bowing out in 2003 although the type was withdrawn from the UK market in 1996. The later A7 and A8 models, introduced in 1990 came with updates to the wheels and brakes, all held in place by beefier 41mm forks, the former enabling more modern rubber to be used but engine power was reduced by around 5% resulting in a slower top speed and standing quarter times.
Kawasaki GPz900R Specifications
Engine
- – liquid-cooled 4-cylinder 4-stroke DOHC
Capacity
- – 908cc
Bore/stroke
- – 72.5 x 55mm
Power
- – 113bhp @ 9500rpm
Torque
- – 68ft-lb @ 8500rpm
Carburation
- – 4 x 34mm Keihin CVK34
Transmission
- – 6-speed wet clutch chain final drive
Frame
- – steel diamond
Suspension
- – 38mm telescopic forks, hydraulic anti dive. Uni-Track rear
Brakes
- – 280 mm discs 2-piston floating-calipers. 270 mm disc 2-piston floating-caliper
Wheels
- – 120/80 x 16, 130/80 x 18
Weight
- – 228kgs
Top speed
- – 155mph
Wheelbase
- – 1495mm
Fuel capacity
- – 22ltrs
Kawasaki GPz900R Gallery
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