Kawasaki ZZ-R 1100 

Back in 1985 Kawasaki launched the GPZ1000R (also known as the 1000RX) and said they would never build a quicker bike. Making 125hp and a top speed of 162mph, Kawasaki claimed the 1000RX would 'outperform competing 1000cc-plus super-bikes for some years'. By 1988 Kawasaki had been forced to think again. The other Japanese manufacturers now had 160mph litre-plus bikes and Kawasaki Heavy Industries had to release a new machine to protect their traditional territory as the kings of top speed and fast engines.

That bike was the ZX-10. It, too, ran 162mph but was lighter and generally sportier than the 1000RX it replaced. By 1990, the other manufacturers were still extracting more speed and refinement from their big bikes; Kawasaki obviously decided the ZX-10's impressive credentials were no longer quite good enough because they unveiled yet another world's fastest candidate -the 175mph ZZ-R1100. 

When Kawasaki's engineers set out to create the world's fastest bike in the late 1980s, they had the advantage of many years' experience in designing powerful four-cylinder engines - plus one very significant technical innovation. The result was a new superbike, the ZZ-R1100, whose liquid-cooled, four-cylinder engine, boosted by a novel 'ram-air' system, produced 145bhp and sent the bike hurtling to 175mph (282km/h).

That level of performance put the Kawasaki far ahead of all opposition when it was launched in 1990, and it remained the world's fastest bike for the next five years. There was much more to the ZZ-R (known as the ZX-11 in the States) than its engine, for it was a refined and efficient sports-tourer. But there was no escaping the fact that the Kawasaki's trump card was its phenomenal straight-line speed.

Forced induction, to give the ram-air system its conventional name, was derived from Formula One racecar technology. It was a sealed system that ducted air from a slot in the fairing's nose, directly

to the unusually large airbox. The faster the Kawasaki went, the more cool air was forced through its carburettors and into the engine.

Intake system apart, the ZZ-R had much in common with the ZX-10, its predecessor as Kawasaki's flagship. Bulbous bodywork held faired-in indicators; the chassis was based on a rigid twin-spar aluminium frame. The new engine shared the ZX-10's liquid-cooled, 16-valve layout but had a 2mm larger bore, increasing capacity to 1052 cc / 64.1 cu-incc. Other changes included larger valves, new

camshafts, lightened pistons, a new curved radiator and a more efficient twin-silencer exhaust system.

When the throttle was wound open above 5000rpm, smooth power sent the bike rocketing forward. It kicked into hyperdrive at around 7000rpm and kept the rider's arms and reflexes stretched as it snarled to the 11,000rpm redline through the efficient six-speed gearbox. In contrast the response below 4000rpm was weak, though an improvement over that of the ZX-10.

High speed composure and stability were remarkable. Even with the scenery and road flashing past at over 150mph (241km/h), the protection of its fairing and the quality of its chassis give the impression of travelling much less rapidly. American magazine Cycle managed a genuine 175mph (282km/h) from their full-power ZZ-R1100. Bikes in many European countries left the dealerships slightly slower due to politically enforced power limits. In most cases these were implemented by carburettor restrictors that were easy to remove.

Although the ZZ-R's frame resembled that of the ZX-10 it was slightly thicker and stiffer, as well as 10mm (0.4in) shorter in the wheelbase. Steering geometry was steeper and the cycle parts were also new. Fork legs were enlarged to 43mm in diameter and, like the single rear shock, were adjustable for rebound damping as well as spring preload.

The ZZ-R was a long, roomy bike that was far too heavy to be mistaken for a sports bike, but it handled well. Much of the mass seemed to drop away on the move, and the stiff chassis and firm suspension gave the Kawasaki a well-balanced feel. It was stable even at high speed, and its triple disc brake system was powerful.

This was just as well, because if any bike needed good brakes it was the ZZ-R. The bike's comfort and practicality contributed to its reputation as a fine all-rounder. Numerous neat details included a comfortable seat, clear mirrors, bungee hooks and a much-needed grab-rail. But all those things were insignificant when compared with the ZZ-R 1100's greatest asset: the magnificent, ram-air assisted motor that generated its all-conquering speed.

D-Model

The D-model capitalizes on Kawasaki's good idea in its sealed air intake system. They've added an air tract on the nose of the fairing to increase the ram-air effect. The airbox is nearly three litre bigger to take the extra wind. Kawasaki reckon the system is 100% more effective. and adds, we estimate, as much as ten horsepower to the bike at top speed.

The changes to the D-model begin with the frame. Which is now of welded stamped sheet alloy rather than extruded box section. It's been redesigned with the intention of making it stronger. Kawasaki must've felt it needed more muscles -  The swingarm's torsional rigidity is up 58%. This redesign has increased wheelbase by 15mm. The steering geometry is actually more relaxed (for high speed stability) with rake going out half a degree to 26.5 and trail 4mm up to 107mm. In contradiction, it actually feels a little more willing to change direction, compared to the '92 model. The only thing I can point to is the change in weight distribution achieved by a new, three-litre larger tank shape which places the bulk of fuel under yer goolies, lowering the centre of gravity. Overall dry weight is up 5kg. The rear wheel now takes a 180/55-17-section tyre; last year's was a mere 170/60-17.
 The disc brakes are 1cm larger at 320mm on the front.