Four stroke, transverse four cylinder, DOHC,
2 valve per cylinder.
Capacity
1089 cc / 66.4 cu-in
Bore x Stroke
72.5 x 66 mm
Cooling System
Air cooled
Compression Ratio
8.9:1
Induction
Bosch electronic fuel injection
Ignition
Electronic, CDI
Starting
Electric
Max Power
108 hp / 81 kW @ 8000 rpm
Max Torque
95.1 Nm / 70.2 lb-ft @ 7000 rpm
Transmission
5 Speed
Final Drive
Chain
Frame
Steel cradle design
Front Suspension
Telescopic coil/air spring forks
Front Wheel Travel
138 mm / 5.4 in
Rear Suspension
Swinging arm with 2 dampers adjustable for
preload and damping
Rear Wheel Travel
99 mm / 3.9 in
Front Brakes
2x 270mm discs 1 piston calipers
Rear Brakes
Single 270mm disc 1 piston caliper
Front Tyre
3.25-18
Rear Tyre
4.25-18
Wheelbase
1540 mm / 60.6 in
Seat Height
780 mm / 30.8 in
Dry Weight
237.3 kg / 521 lbs
Wet Weight
255 kg / 562 lbs
Fuel Capacity
21.4 Litres / 5.5 US gal
Consumption Average
38.8 mpg
Standing
¼ Mile
11.5 sec / 118 mph
Top Speed
137 mph / 220
km/m
With its blight reel paintwork,
fancy new initials and high-tech fuel-injection system, the original GPz1100
was the biggest and fastest of a new three-bike range of high-performance
fours that brought Kawasaki storming into the 1980s. But once glance
confirmed that the big GPz was very much a superbike of the old
school, with an air-cooled, two-valves-per-cylinder engine, twin-shock
chassis and generous supplies of both power and weight.
Even at a standstill, the GPz was
an imposing motorcycle. Its angular styling made no attempt to hide the fact
that this bike was not built to be messed with. Its seat was high, its
wheelbase was a long, and it weighed a substantial 5621b (255kg) with fuel.
The engine's capacity of 1089cc was slightly smaller than that of Yamaha's
rival XSI100. let alone Kawasaki's own Z1300 six.
But with a peak output of I08bhp
at 8500rpm. the GPz was the world's most powerful four in 1981.
Kawasaki needed that credibility
boost, because the Big K's reputation for all-conquering performance had
slipped since the mid-1970s heyday of the Z1 and Z900. Unlike its rival the
16-valve Suzuki GSX1100. the GPz relied on Kawasaki's age-old format of two
valves per cylinder.
But the new motor
was substantially uprated from that of the Z1000H EFI. which had become the
world's first fuel-injected roadster 12 months earlier.
Capacity
was increased by
boring out the cylinders to give dimensions of 72.5 x 66mm. and the larger
pistons had higher domed crowns to increase compression ratio. The new motor
had bigger valves and revised timing for its twin cams, the crankshaft was
lightened, the five-speed gearbox strengthened and an oil-cooler added
between the frame's twin downtubes.
Uprated chassis
The GPz's chassis was also based
on that of the 1000H. with numerous modifications. Its main frame tubes were
made from larger-diameter but thinner-walled steel. Rake and trail
dimensions were increased. Front forks were 38mm in diameter and
air-assisted. Rear shocks could be tuned for rebound damping as well as the
normal preload. All this was state-of-the-art for a Japanese superbike. So
too was the bike's large instrument console, with its voltmeter and fuel
gauge set between the speedometer and rev-counter.
Those dials got to record plenty
of action. With its big valves and hot cams the GPz liked to be revved,
tugging hard on its rider's arms as it howled through the gears towards the
8500rpm redline and a top speed of around 140mph (225km/h). Acceleration
away from the line was ferocious, making the GPz motorcycling's
straight-line king in 1981. And its mid-range delivery was excellent, too. The
fuel-injection gave a crisp response, sending the bike surging forward even
from below 3000rpm in top gear.
Stability at speed was good
provided the GPz was pointed in a straight line and the throttle was held
open. Competent suspension meant that the big bike could be good fun in
corners, too. But braking and changing direction at the same time was more
than the chassis could take without complaint. The GPz was slightly lighter
than its Z1000H predecessor but there was still a lot of metal to throw
around.
Kawasaki moved quickly to update
the GPz. adding a handlebar fairing in 1982. and a year later revising it
further with a larger, solid-mounted fairing plus single-shock rear
suspension. In 1984 came a bigger step: the liquid-cooled. 16-valve GPZ900R.
That was the bike with which Kawasaki entered the modern era. but its debt
to its predecessor of 1981 should not be overlooked. For itwas the
first big red GPz1100 four that restored Kawasaki's justifiably proud
reputation for full-blooded high performance.
Source of review: Fast Bikes by Roland Brown
Model History
The 1981 GPz1100 was the first 1,100 cc motorcycle released by Kawasaki. It
was officially marketed as the GPz1100 B1. Its frame design was a typical cradle
design and the engine was based on the earlier Mk2 engines of the z1000H and
z1000J, but the engine capacity was increased to 1,089 cc.
Rather than featuring carburetors, the B1 was fitted with electronic fuel
injection (EFI) as used on the earlier 1980 Z1000G/H models. The key cosmetic
change was the paint scheme and the return to a painted black engine similar to
the original Z1 released in 1973.
Suspension and braking was similar to earlier models; the front forks
featured 38 mm tubes, the frame design, based on the z1000H and J models was
made from larger diameter steel in the section between the steering head to rear
of the tank. To reduce weight, the tube walls were thinner. It weighed 255 kg
(562 lb) with a full tank of fuel, and the power output was claimed to be
108 bhp (81 kW)
The B1 was followed the following year by the GPz1100 B2; the B2 featured a
cockpit fairing, the use of LCD warning lights and improved engine coating using
a black chrome finish instead of the previous black paint. Kawasaki was serious
about having the best Superbike, and the B2 was changed in several significant
ways over its predecessor.
The engine output was increased by increasing the valve lift from 8.3 mm to
8.7 mm, and valve duration was increased from 280 degrees to 288 degrees to
boost upper-end horsepower. The early BOSCH-type analog fuel injection was
scrapped, and a new digital fuel injection (DFI) was used in its place. The new
system did not use the 'flapper' to measure airflow, but a digital
microprocessor, a series of sensors, and a throttle position sensor to meter the
fuel much more accurately, eliminate throttle lag, and decrease emissions.
The suspension calibration was all-new for 1982, to make the big GPz an even
better handler both on the track and on the street. The fork had slightly
stiffer springs, and compression and rebound damping were increased
approximately 10%. In the rear, the Kayaba shocks used the same springs, but
with greater pre-load, and the compression damping was effectively doubled. And
each of the rebound adjustments offered 30% more damping than its '81
counterpart. Wider, Dunlop K300 tires replaced the Bridgestone tires used on the
B1 to improve handling and steering response. The B2 was also offered in a gold
colour finish called "Sonic Gold".
The B1 and B2 were the last of the large-capacity dual-shock motorcycles from
Kawasaki.
In 1983 a new GPz1100 design was released that featured Unitrack single
suspension, anti-dive units on the forks and a major styling overhaul often
called the "swish" look. Known as the ZX1100A1 model, the 1983 model featured a
larger fairing (with a lower fairing section as an option to give a full race
fairing), different instrumentation and a warning panel mounted on the
redesigned petrol tank. This model contained many features that were to appear
on the GPz900R model leading to the suspicion that it was used to test the
acceptability of newer technology such as Unitrack and Anti-Dive forks and the
newer styling. The 1983 model featured the same EFI design with a few small
modifications, such as the inclusion of a warning light that flashed service
codes when the DFI system was having a problem, a rev-limiter, and a 'limp' mode
that would allow the engine to keep running if one of the sensors failed.
The engine design changed in the 1983 model to use underbucket shims similar
to the z650 and the camshaft duration was increased from 288 degrees to 300
degrees, and the valve lift increased from 8.7mm to 9.5mm. To flow more air, the
head was revised extensively from the earlier model, featuring new ports, a
'bathtub' combustion chamber borrowed from their own S2 racer, and a 1mm larger
intake valve recessed into the head slightly for valve clearance. The power
output was now claimed to be 120 bhp (89 kW) at 8,750 rpm.[2] CYCLE magazine
recorded 104 rear-wheel horsepower on their dynamometer, and Kawasaki was hoping
to have a solid 10-second quarter-mile machine, but the increase in power at the
upper RPM ranges lowered the torque at lower RPM's, so taking advantage of that
power anywhere but on a racetrack was difficult. This model was released in a
Red paint scheme with Blue and Silver stripes. Fundamentally the engine was
still the same as earlier air-cooled engines.
1984 ZX1100-A2
The 1984 model deviated little from the 1983 model but featured a new paint
scheme called "Galaxy Silver"; the original Firecracker Red scheme was still
available. Revisions were minor and include a revised exhaust system and the
addition of panels under the instrument cluster. Sales were now in direct
competiotion to the smaller, lighter, water-cooled GPz900R model, which by the
end of 1984 would win first, second and third place in the Isle of Man TT races.
1985 ZX1100-A3
In 1985 the last GPz1100 was released, competition from sales of the GPz900R
released in 1984 had surpassed the GPz1100, so the 1100 was discontinued. All
specifications from previous models were retained. This was also the final year
for the GPz750 Turbo, which used much of the technology from this series of
motorcycles.
Later models
Main article: Kawasaki GPZ1100 Sport Touring
In 1995, Kawasaki re-released the GPz brand, basing the motor on the
ZX-9R/ZX-10/ZX-11/ZZR-1100 water-cooled engines. There is no similarity between
the later models (officially designated as ZX1100E) and any earlier models. This
carbureted model was available from 1995 through 1997 in red or black and some
came with rare factory ABS and/or saddlebags options.