Kawasaki Z 750E
Horsepower rules. A philosophy which gives rise to such excesses as eight-litre automobile engines and 250 horsepower marine outboards. Never mind that most giant-engined American cars came with crossply tyres (albeit whitewalled), slushy suspension, vague steering and jamtin drum brakes. And never mind that giant, six-cylinder, two-stroke (to keep the weight down) outboards consume more fuel than a bulldozer with the choke on. Power is all, bigger is better and biggest is best. Weight is especially important in two wheeling, far more so than in tintop-ping or other transport modes. The single most-cherished aspect of motorcycling machine response — is diminished directly with each extra kilogram. The real heavyweights are invariably clumsy, awkward and ponderous compared to what they might have been, although clever engineering can disguise the ill-effects. Oddly enough, the second genuine lightweight out of Japan is a product of Kawasaki Heavy Industries, the same Aiding the lack of mass are a low seat height and a low centre of gravity. The Z750's frame is basically the same as the Z650's, save two minor details — the engine was relocated slightly to improve high speed stability and the toptwo frame rails were lowered 20 mm to reduce the seat height. Suspension of course had to be upgraded for the Eighties and the Z750 comes with air-assisted forks and adjustable damping rear shock absorbers, both from Kayaba. Cornering clearance is increased over the 650, the three drilled disc brakes use Kawasaki's sintered metal pads for improved wet weather stopping and the old tungsten headlight and puny, single horn soldier on. Other additions for the new model include electronic ignition, tamper-resistant brake fluid reservoirs (you need a Phillips head screwdriver to tamper now), an ignition switch steering lock, hazard lights, a stepped seat you may not like and a positive neutral finder you will like. On the debit side, the styling is dated (although the bike is far from ugly), the colour drab (subdued might be kinder) and the instrumentation is in need of updating. A voltmeter has been added for the Z750, but we'd prefer an oil temperature gauge on a highly tuned, plain-bearing four without an oil cooler. Outback temperatures get very high in summer and the 750 is certainly a tourable motorcycle. Final drive is by roller chain rather than the more convenient shaft of Yamaha's XJ. Engine Beyond any doubt, the Z750 is endowed with an outstanding power-plant. Based on Kawasaki's 652 cm3 four it may be, but this 738 cm3 version delivers such hearty performance it's almost impossible to believe the two are from the same mould. And not only is the larger engine's performance up, on TWO WHEELS' test figures its economy is significantly improved too. Starting with the Z650 four, Kawasaki increased the bore size 4 mm to 66 mm, leaving the stroke at 54 mm. A reworked head using 1 mm bigger inlet and 2 mm larger exhaust valves was also developed and this, together with new pistons, resulted in a 9.0:1 compression ratio for the new engine. Claimed power is now 55.2 kW (74 hp) at 9000 rpm, measured at the engine crankshaft. Helping the new head and bigger pistons do their thing are a quartet of 34 mm constant vacuum Keihins (not, as most magazines will tell you, Mikunis), the largest carbs on any Japanese 750 by the way, and a pair of less restrictive silencers. The new mufflers are slightly growlier at idle and low to midrange revs, but didn't seem any noisier at peak revs. This means the bike is a shade louder than the Z650 in around town running, which to our minds is a, good thing. So many whisper-quiet bikes are now emanating from Japan that careless car drivers will soon be able to add "I just didn't hear him, Officer" to the usual "I just didn't see him, Officer". The little bit of extra road presence is nice, and perhaps a few less Z750 owners will feel the need to buy a (probably too noisy) four-into-one. The engine is finished in black with contrasting polished alloy covers (a la Z1000s) and is generally designed to minimise regular maintenance although the cams must still be removed to adjust valve clearances. The Z750 produced such good torque at low revs that little warmup time was needed before riding off and the choke could be pushed home very early in the piece. Both of our test bikes, one with 9500 km on the clock, the other with 200 km up, were noisier mechanically than we expected, es- The Z750 is a nimble bike, and is let down by oversprung rear suspension in only the roughest, bumpiest corners. Fuel consumption has taken on a new importance but Z750 buyers have less to fear than most 500 cm3 and over bike owners. The Z is the first really high performance 750 (it is, as we shall see, the fastest 750 on the market) which has averaged better than 50 miles per gallon on a TWO WHEELS test, the closest to date being Honda's 16-valve CB750K with a 15.9 km/litre (45.2 mpg) average. The old Z650 with far less power than this 750 and Yamaha's shaftdrive XJ650 both averaged 15.9 km/litre as well, primarily because both bikes need to be revved fairly hard if the rider is in any sort of hurry. By far the biggest factor in the excellent fuel economy of the 750 is the lack of need to drop gears to obtain decent acceleration. The engine is incredibly torquey at low revs — the "powerband" seems to extend from idle to redline — and the light Z750 virtually pours on the km/h the instant the throttle is opened (unless one is in a totally unsuitable gear). It really is surprising how fast this Kawasaki will go without resorting to abnormal, banzai riding styles. This good low-rev-power/light weight relationship also means the Z has megabike type instant pickup available for accident-dodging manoeuvres should you ever require it. A definite primary safety plus. Performance To answer the questions you're all asking first, the Z750 gobbled up Castlereagh Dragstrip in 12.4 seconds at 172 km/h (several times), topped out at a true 204 km/h (though the speedo would have you believe it was 215 km/h), pulled 41.7 kW at 9500 rpm on Stewart's dyno and peak torqued at 42.8 Nm at 9000 rpm. This remarkable torque spread shows best the Z's strength at low crankshaft speeds although comparing its power at low revs with that of its rivals is interesting too. It is worth noting as well that even if the Z made only the same power at low revs as the Transmission Straight-cut primary gears transfer power to the beefed up clutch and then through a normal five-speed constant-mesh gearbox and endless secondary chain to the driving wheel. Kawasaki has included a positive neutral finder on the Z750 but this works a little differently to the one fitted on one-litre Kawas. The ZI000's neutral finder is in fact a positive neutral stop between 2nd and 1st gear on the way down through the box and allows normal, upward 1-2 changes. The Z750's neutral stop is between 1st and 2nd on the way up the gears, but it only operates when the bike is stationary and a normal, one step 1-2 change occurs when the bike is mobile. Overall gearing is excellent, the Z750 almost pulls redline revs in fifth at top speed and the internal ratios are evenly spaced and sensible. There is a touch more drivetrain lash than we'd like, but less than most Hondas suffer from and we're not complaining. The clutch lever has a mildly firm pull but the operation of the clutch itself is faultless. The toe-bar of the gearlever is made of rod that's too thin and the placement of the lever relative to natural foot/ankle angles seems poorly thought out. The footbrake lever suffered a similar malady, one always seemed to have to move the right foot deliberately outwards, upwards, inwards and then down onto the pedal. Playing with the adjustments helped a little but we thought both the brake and gear levers were too close to the pegs. And the double gear linkage seemed too spindly and fragile, most un-Kawasaki-like. Handling, steering and suspension Steering is superb and handling is very good. The Z750 is Kawasaki's best offering in these areas for some years. The steering particularly is state of the art. One sits into the Z and the bike feels right to the rider in the same way, but perhaps not to quite the same extent, as Yamaha's brilliant XJ650. Nonetheless the bike is basically a forgiving mount, secure one- or two-up and easily able to cope with midcorner braking or line changes. Flicking the Z through S-bends is pure exhilaration — it feels more like a 400 than a full-blooded superbike. No complaints at all with the braking (aside from footpedal location), we found the stoppers reliable, powerful and as fade free as most. Stopping distances were good, as was feel at the controls and we like the good-looking, all-black, rectangular fluid reservoir for the front discs with its screw-down lid and clear sightglass. A nice anti-vandalism touch although we don't know anyone who's had their front brake sabotaged. Still, kids might be deterred. The fuel tank's capacity is rather less than some 750s at 17.3 litres, but the thrifty Z stretches this out to a reasonable touring range so no demerit marks here. Reserve is a smallish 1.7 litres, though. Switches are standard Kawasaki units (manual blinkers only) and do the job satisfactorily, which is more than can be said for our testbike's speedo which was (excuse pun) miles out. It read 11 percent high at 60 km/h (an indicated 60 is a true 53.3 km/h), 8 percent high at 100 km/h (100 equals true 92) and was only 5 percent high at 200 km/h (200 equals true 190). Entirely unsatisfactory although, strangely enough, the odometer was only 2.2 percent out when we checked it prior to calculating true fuel consumptions. Conclusion Kawasaki has taken the bit between its teeth and shown it will cater for all tastes — those who want silky smooth, six-cylinder, battlecruiser-cum-tourers and those who want genuine lightweight high performance sportsters. This augurs well for the company's future as well as our future as motorcycle buyers. Source Two Wheels 1981 |