Kawasaki Z750E Road Test
Kawasaki haven't had a hot 750cc sports machine in
their range since the demise of the H2 two-stroke
triple five years ago — only the cooking Z750
So not surprisingly, the factory's late entry into
the 750cc sports arena, even tougher now since the
entry of Suzuki's sixteen-valve four alongside Honda's
similar offering, meets the opposition head on.
But Kawasaki haven't take taken the same all-guns-blazing
super-high-technology approach as either of the other
two factories. Instead they've made their new Z750E
four relatively light and simple. Basically the bike
is a bored out Z650 with a slightly modified frame.
So the new seven-fifty weighs about the same as the
six-fifty, 4621bs dry making it 461b lighter than
Suzuki's GSX750 and a whacking 581b lighter than the
Honda CB750. That gives the Kawasaki a significant
advantage in handling since the bike is still very
compact as well as placing it slightly ahead of the
Suzuki in its power-to-weight ratio.
The Z750E's cylinder bores are 4mm larger than the
Z650 at 66mm which with the same stroke of 54mm give
gives a capacity of 738cc. To improve the breathing
of the double overhead cylinder head, the valve sizes
are increased and the angles changed to suit the larger
bores while the timing of the valves is lengthened
to 30/60-60/30 from the six-fifty's 22/52-60/20 giving
270 degrees of inlet and exhaust opening from 264
and 260 degrees respectively.
The result is that the Z750E is significantly more
flexible and higher revving, developing its maximum
power of 74bhp at 9,000rpm from the Z650's 64bhp at
8,500rpm. And to allow that extra power to be more
effectively used the engine breathes through a quartet
of 34mm constant-vacuum Keihin carburettors instead
of 24mm piston-slide types.
If you think the new Kawasaki should therefore be
a flyer, then you're right. It is is. When I rode
the machine recently at Donington Park the acceleration
was on a par with the Z1000 up to 80mph, which gives
the impression that both Honda and Suzuki have got
a fight on their hands — and from a bike that's
just a modification from an earlier model.
Gearing has been raised slightly from the 650 by
the use of a higher final drive ratio, 33/13 that
gives 120mph at peak power revs. The red line is at
9,500rpm, so if the engine will rev out in top the
bike should reach the claimed 126mph top speed. Internal
ratios of the gearbox remain the same but we are worried
about the use of a 13 tooth gearbox sprocket —
it's far too small for comfortable chain life.
With all the extra power you would also expect the
Z750E to be a lively handler. And on a race track
it does feel that way. But Kawasaki have uprated the
suspension by the use of air pressure to supplement
the coil springs in the front fork and have fitted
rear units with four-way adjustable damping as well
as spring preload adjustment.
The spring rates are hard, as you might expect of
a super sporting machine, and the ride is on the rough
side. But this means that the bike doesn't squat during
cornering and the bike can be leant to amazing
angles without grounding. The Dunlop Gold Seal tubeless
tyres give the first hint of a limit when powering
hard out of a corner with slight drifting but it is
perfectly predictable and the throttle control is
delicate so control is better than on the 650.
What was true about the Kawasaki 750 was that it
felt exciting. It may be due to the fact that there
is a lot of power in a small motorcycle — a
perfect recipe for fun (vis the Yamaha RD400). But
it is short with a 55.9in wheelbase (helping the cornering)
and the steering is taut and positive, using the same
geometry as the 650.