This four-stroke four-cylinder motorcycle boasted double overhead camshafts just
like the bigger Z1 and Kawasaki claimed 64 bhp (48 kW) from the 652 cc motor.
Unlike the Z1, the 650 used a plain bearing crankshaft with a HyVo multiplate
chain primary drive instead of a gear drive. This system necessitated the
installation of a third (intermediate) shaft in the transmission to drive the
input side of the clutch.
Also included for this model year only was a three phase excited field type
alternator. Subsequent years of all models (until 1981) were equipped with a
single phase permanent magnet (or shunt type) alternator.
Another departure from the Z1 engine design was the use of a shim-under-bucket
method of setting valve clearances. The Z1 engine employed a shim-over-bucket
design for this purpose and there had been reports of the camshafts actually
forcing the shims in the Z1 engine out of position with consequent damage.
Project leader Inamura made sure this would not be a problem with the 650
engine. A single 245 mm disc was used up front with a 250 mm drum on the rear,
more than enough to handle this relatively lightweight bike. Both front and rear
fenders were chrome.
1977 KZ650-C1
This model was offered only in North America (and possibly Japan). It was named
the Z650 Custom and was introduced in early 1977, somewhat later than the B1.
The C1 model differed from the B1 model in the following areas: it had cast
alloy seven spoke wheels instead of conventional spoked items like the B1; disc
brakes both front and rear with dual discs at the front having the calipers
mounted behind the fork legs. It had different fork bottoms to cater for the
rear mounted calipers. The C1 also sported four-way hazard flashers, which were
not fitted to the B1.
Kawasaki's Z650 four has carved itself an businessman spending a day helping
his corn-enviable reputation for speed and stamina since panion to hospital
after a crash and after side-it appeared in late 1976. Proof of the speed came
swiping a kangaroo hard enough for Rich to think at Daytona in the following
March when he had broken a leg. The Z650 never missed a beat. Kawasaki attacked
the world 750 cc endurance We were not quite so adventurous during our records
with a trio of mildly modified Z650 own 600-mile road test but we learned that
those roadsters. They came away with a bunch of records were no fluke. Firstly,
there is no doubt records that would have been impressive for a that the Z650 is
very fast. It can accelerate to 60 1,000 cc roadster, let alone a 650. Best were
the mph as quick as anything you can buy on wheels. FIM world 1,000 km at 128-4
mph, the If proof was ever needed that there is only one AM A/FIM six-hour at
127-7 mph and the AMA thing better than a fast big bike, and that's a fast
100-miler at 130 mph. For good measure they small bike, the Z650 is it. rounded
off with the world FIM 24-hour record For motor cycles, small is definitely
beautiful, at 117-2 mph. Earlier, the American, Rich Willet If there is one
thing that hampers the enjoyment attacked the round the coast Australia record
on of a bike, it is weight and bulk. The bulkier and his Z650 with a colleague.
Just over ten days later heavier a machine the more difficult it is to he was
back at Sydney having covered 9,550 manouevre, the more trouble it becomes when
miles to beat the record for the toughest trip in cornering and the more fuel it
uses, motor cycling by the scant margin of one hour. The Z650 Kawasaki is
tangible evidence that This was despite the 44-year old St Louis smaller is
better. At 495 lb, it weighs some 30 lb lighter than most of the seven fifties
and with a 56.6-in wheelbase is about 3 inches shorter. On the road the bike
gives away nothing in performance and is far and away a better performer than
550 cc machines. Flat-out mean top speed at MIRA was 119-6 mph, only 4 mph down
on Suzuki's GS750 and 2 mph less than the Honda CB750F1.
Even more stunning is its acceleration. Taking to the test track like a drag
racer, the Z650 scorched through the quarter-mile in 12-9 sec with a terminal
speed of 101-6 mph. Although eight runs were timed, six of which were 13 sec or
under, the bike finished as unruffled as ever.
The secret is not only the power of the twin-cam 652 cc short-stroke,
four-cylinder engine, but the bike's perfect gearing and balance. The Z650's
wheelbase is neither so short as to provoke unmanageable wheelies on take-off
nor so long that there is too much wheelspin.
Drop the clutch at 7,000 rpm and the Kawasaki just digs in and gets on with
the job, the front wheel just hovering above the tarmac for the first few yards.
It is as though the bike was made for drag racing. The proof of this is that the
Z650 is one of the quickest bikes from rest through 110 yards. The terminal
speed of 66.8 mph has only been beaten once - by the super-fast 1973 Kawasaki Z1
903 cc four at 68 mph. It can reach 50 mph in just 3 sec from rest.
Yet the bike is no awkward rev-happy racer. Although it can scream up to
10,000 rpm (the red line is at 9,000 rpm), the engine is sweet and flexible
enough to haul along at under 4,000 rpm and there is torque enough to give a
sizeable kick in the seat as you open up.
Apart from a band around 7,000 rpm, the Z650 is exceptionally smooth for a
four in-line, particularly at about 70 mph in top gear (equal to 5,500 rpm.)
This makes it very relaxing to ride at speed, particularly as there is hardly a
hint of 'cammyness' with ample response throughout the range.
Power characteristics like this usually result in above average fuel economy,
but although the six-fifty four could return 52 mpg around town, the overall
test figure of 46-5 mpg was lower than expected, but doubtless due to the heavy
consumption of 34 mpg during the performance testing. Range on the 3£ gallon
fuel tank is between 150 and 160 miles.
Although Kawasaki claim the machine will run on unleaded fuel like the Z1000,
in the case of the test bike unless it was run on four-star fuel it would
detonate at small throttle openings when pulling hard. This off-idle weakness in
the mixture strength was probably connected with the Z650's excessive
cold-bloodedness when starting from cold. The process of starting is made more
tricky by the need to disengage the clutch when pressing the starter button.
Excellent though the machine is on the track or when ridden hard, the Z650 is
not quite so impressive when the going is more relaxed. At low speeds, for
example around town streets, the gearchange hangs up and is very clunky,
particularly when engaging bottom gear from neutral. On the open road, the
gearbox which is identical to the unit on the Z750 twin, is by contrast as slick
and crisp as you could want.
Town riding is further spoiled by the excessive backlash in the gearbox,
which is compounded by that stuttering in the carburation.
Being much smaller and more compact than the Z1000, the Z650 has none of the
bigger model's awe-inspiring bulk, and it is a markedly better handling machine.
Although the suspension is softer and more comfortable than the big model one
can skim through bends much more confidently than the Z900 or Z1000 would ever
allow, and with none of the gut-churning high-speed wobbles that still mark the
Z1000 as a bike to be respected when the going gets hot.
The main improvement on the Z650 is a stiffer frame with more sensibly
designed steering geometry. The rake of the front fork has been pulled back to
63 degrees, in line with the Z750 twin, and combined with more trail. The bike
is very stable in fast bends, while at low speeds there is only the slightest
hint of 'oversteer' - that feeling that the bike wants to drop further into a
corner - and unlike the Z900 it does not want to straighten up when cranked over
in fast corners.
Ground clearance is enhanced by use of one silencer either side and the only
limitation on the amount you can crank the bike over is the grip of the Dunlop
Gold Seal tyres. If you manage to touch down the left side projection of the
main stand you are a long, long way over.
Harder riders will prefer stiffer springs on the Z650, for although it is
very much a sporting bike, the suspension has been tailored to have a broader
appeal. The 100 lb/in rear springs give a smooth ride and the dampers are fairly
well matched - like the front fork.
H owever, there is still some of the vagueness in the overall feel of the
machine that puts it not quite on par with the best handling roadsters now
available.
Like the GS750 Suzuki, the Z650 has been well planned for the rider. The seat
is soft yet secure enough to prevent you moving about, and the footrests are
well tucked in.
The lowish handlebar is properly swept back at the right angle and can be
adjusted to taste even though the wiring runs neatly through the tubing. Only
general criticism of the Z650 is that the shortness of the bike will put off
taller riders. Cruising at anything over 70 mph becomes tiresome after only a
few minutes due to the height of the handlebar grips.
Along with practically all other Japanese bikes the Z650 has a
stainless-steel, front-brake disc which is fine when dry, but always has to be
allowed for when wet and cold. Kawasaki sensibly resisted the fashionable
temptation to fit another to the rear wheel, and retain a 7-in drum brake. This
works admirably, the brakes being neither too grabby nor under-powered.
Electrical equipment, apart from the headlamp, is first class. A high power
280-watt alternator supplies all the needs of the system and the battery never
went limp after days of slow commuter riding. Indicators are large and bright.
However, the headlamp suffers from being indistinct and lacking in penetration
on both dipped and main beam.
The heart of the Z650 is its modern power unit. Quiet and unobtrusive, it
whispers along with hardly a rustle from the valve gear or exhaust. At 70 mph in
top the engine is barely audible above wind roar. Designed specifically with
quietness in mind, it shares more in common with Honda's CB500 four. Unlike the
Z1000 with its roller bearing crankshaft and gear primary drive, the Z650 uses a
plain bearing crank with a Morse type chain running to a shaft between the crank
and the clutch, which is driven by gears. For longevity, the valves are opened
by twin-overhead camshafts and bucket followers and although the Kawasaki
service book says that valve clearances need checking every 3,000 miles, it is
claimed that they will not need attention until four times that distance. That
is just as well, for the camshafts need to be lifted to vary the 47p shims under
the buckets.
Longer servicing intervals are becoming more and more common; details like
the sight window on the engine to check oil level ease the work. The rear chain,
although very costly, pays its way by lasting up to 700 miles before needing
adjustment thanks to the use of O-rings to keep the oil in the links and the
dirt out.
Undoubtedly, the Z650 is the best Kawasaki so far. It restores the image of
thundering power and speed with a new one of civilised restraint. The Z650 can
afford to be sober in appearance because it takes on the 750s and just about
equals them at their own game.
Road Test 1976
Any corrections or more information on these motorcycles will be kindly appreciated.