Air cooled, four stroke, parallel twin cylinder, SOHC
Bore x Stroke
64 х 62 mm
36 hp @ 8500 rpm
3.3 kgf-m @ 7500 rpm
5 Speed / chain
Old John D. Rockefeller was a supreme realist and
as such naturally had little enthusiasm for innovation. He once told an
interviewer that pioneering was risky business; the sure-fire way to succeed
simply was to copy success. A good plan? It was for Rockefeller, who accumulated
a megamillion-dollar fortune back when the shiny new dimes he gravely doled out
to importunate widows and orphans still would buy a crust of bread.
Rockefeller's law of applied economics has guided
many business decisions, and we now find evidence that it is at work in
motorcycling. Saleswise, Honda's CB-350 twin was one of the all-time great
motorcycles. At least a half-million of that model were sold in America alone.
It was inevitable that people would try to duplicate the CB-350's success by
substantially duplicating the motorcycle, and that's what has been done: Honda
itself has made a try, with the new CB-360 we tested in our December, 1973,
issue; and now Kawasaki has crowded into the act with a new model—the KZ 400.
Kawasaki will not thank us for comparing the KZ
400 with Honda's CB-350, but there are similarities so obvious as to demand
comparison, though in fairness to Kawasaki this should not be carried too far.
One underlying yet still easily detectable similarity is in intent: ride the KZ
400, even if only around the block, and you'll know it was designed to do things
the way the CB-350 did them—but a little faster and better. And far more
similarities than differences exist in the appearance of the KZ 400 and CB-350.
This last is especially true of the two bikes' engines, which are strikingly
alike, right down to their scantily-finned cylinders and primary case shapes.
None of this is to say Kawasaki's KZ 400 actually
is a copy of the Honda CB-350. Similarities do exist in terms of appearance and
feel; otherwise they are very different motorcycles, as should be expected.
Honda's CB-360 proves through its existence that the old CB-350's makers did not
consider it good enough for 1974. It is reasonable to assume that Kawasaki also
had in mind a successor for the CB-350, and certainly not just a copy.
Kawasaki has worked a general improvement over
anything else in the under-400cc street bike class by providing the KZ 400
engine with a Yamaha-style balancer, a contra-rotating counterweight housed in a
bulge on the front of the crankcase and driven by a chain reaching back to the
crankshaft. This balancer subdues most of the shaking otherwise to be expected
from a vertical-twin engine, which is a plus all by itself. But Kawasaki also
has taken advantage of the relative freedom from vibration and bolted the KZ
400's engine solidly into its frame. Chassis rigidity and thus stability is
served by using the engine as a frame brace—and in the KZ 400 the balancer
minimizes the magnitude of the payout in variable-diameter handlebar grips.
For the KZ 400, Kawasaki has produced a frame
that doesn't seem to need much assistance from engine bracing. A backbone tube
of substantial diameter forms an inherently rigid connection between the
steering head and the tubular fork above the swing arm pivot, and the big
widely-spaced lugs behind the transmission housing tie very solidly into the
pivot supports. There is evidence throughout the structure that Kawasaki's
engineers were determined to avoid the flexi-flyer effect in the KZ 400, and
Cycle's theorists grudgingly admit that, in all, it's a nice piece of work.
All theory aside, the KZ 400 really does handle
pretty well. It's not quite as nimble as the CB-360 with which it inevitably
will be compared by buyers, but the KZ 400's handling certainly cannot be termed
heavy. Kawasaki has followed closely the current Japanese practice of providing
nearly all street machines with a steering head angle, or rake, of 27-degrees
and combined that with a longer-than-normal trail of 4.13-inches. This steering
geometry combines with the KZ 400's weight distribution to give nicely neutral
steering and a straight-line stability that's worth its weight in gyroscopes
when you're facing gusty sidewinds or following freeway rain-grooves. We
especially liked the steering's neutral feel. Most bikes' front wheels tend
either to steer into or out of turns, requiring the rider to hold a little
pressure on the bars, and many have steering that changes character with speed.
The KZ 400 almost seems to aim itself, and holds its line around turns with
commendable precision—as long as the road surface is fairly smooth.
Unfortunately for the KZ 400, things like frame
rigidity and the matching of weight with steering geometry are only the
foundation for good handling and not the whole package. Before it will handle
really well a bike also needs good tires and a suspension system that will keep
those tires firmly in contact with the road. And in certain of these areas the
KZ 400 is sadly deficient.
The Kawasaki's Yokohama tires seem to be fine,
but we can't be sure. The bike's suspension is bad enough to obscure all but the
most obvious of tire-performance characterictics. Sporting riders won't be
impressed with the Yokohamas because they have very soft carcasses and squirm
around a lot under the loads imposed by hard cornering and braking. But those
same characteristics lend them an ability to envelop road irregularities, reduce
ride harshness, and provide the insensitive rider with enough control feedback
to keep him from straying into trouble.
It is good that the KZ 400's tires do not
encourage spirited riding, because the bike's suspension lapses into raging
protest when it is ridden hard and sometimes even when it isn't. Here again we
are confronted with symptoms masking other symptoms: we think the front
suspension is inadequately damped but can't be sure, as most of what the fork
legs might be doing or failing to do gets obscured by the commotion back at the
rear wheel. We do know that a ferocious hopping of the front wheel can be
provoked with hard application of the front brake; all else is sicklied o'er
with the rear suspension's misbehavior.
Very nearly all that can be said of the KZ 400's
rear shocks is that they do provide a convenient strut-mounting for the springs.
It must be assumed that the oil inside the damper bodies—if any—is there merely
to keep them from squeaking, as the control exerted over wheel movements is so
slight as to be undetectable. Somebody in a decision-making slot at Kawasaki
clearly has failed to grasp the fundamental difference between "inexpensive" and
"cheap." Maybe it will help if we tell them, here, that the KZ 400 is a
relatively inexpensive motorcycle taken as a whole, but handicapped by shocks
that are overwhelmingly, miserably, abominably and infuriatingly cheap.
Neither were we exactly enchanted with the KZ
400's brakes. By all that's right and holy the front brake should work extremely
well, and it's obvious that plenty of thought went into designing the disc and
caliper. Most of the bikes from Japan have brake discs made of a stainless alloy
steel, which resists rusting but really doesn't help the brake function as a
brake. The KZ 400's disc is a one-piece casting and appears to be mostly iron
with a bit of nickle to keep down corrosion, and it should function better than
a stainless disc. Similarly, the caliper mounting promises much: it is attached
to the fork leg through a hall-joint swivel, and there is every reason to expect
that this arrangement would allow the pads to pull up squarely against the disc
at all times. Finally, there is the caliper itself: a very hefty hunk of metal,
and not likely to cause problems by flexing. Yet, although all the brake's
various elements seem to be near-perfect, its performance leaves much to be
desired—as does that of the drum-type rear brake. In our standard braking test,
consisting of three maximum-effort stops from 60 mph, the KZ 400 averaged
.815-G. Not bad, but well short of the .9-plus number we get with most
One reason for the Kawasaki's relatively poor
showing in the braking test was that its response to control input is uneven.
Actually, the back brake's response is fairly consistent: nothing much happens
when you first dab at the pedal and the brake keeps right on working at the
nothing-much level no matter how hard you stomp. At the front brake you get a
disconcerting shudder and a soggy response when the lever is squeezed
middling-hard but the bike doesn't seem to be in any hurry to stop. So you
squeeze harder and harder, and eventually find that there is a point at which
braking ceases to lag behind control pressure and begins to gain very fast,
progressing straight into lockup if given half a chance.
What the KZ 400 lacks in brake system response it
almost compensates with the splendor of its carburetion. It has a pair of Keihin
CVB carburetors with 36mm throats, butterfly throttles and a pull-open/pull-shut
dual cable connection with the twist grip. These are constant-vacuum instruments
much like those first seen on Honda's CB-450, with piston-type vacuum chambers
instead of the more widely used and cheaper diaphragms, and they provide
wonderfully clean running. There's never a wheeze or stumble. The only criticism
we have is that the engine's response to the first few degrees of twist-grip
rotation is awfully sudden, and made worse by lash in the drive train. It is of
course very typical of Japanese bikes with CV-type carburetors. Kawasaki's KZ
400 is somewhat less afflicted with the problem than Honda's CB-360 or the
All previous Keihin CV carburetors have had
butterfly-type chokes for cold starting. Those on the KZ 400 are equipped with
Mikuni-style mixture enrichers, and they probably contribute greatly to one of
the Kawasaki's more appealing characteristics, which is its willingness to start
no matter how chill the morning. Flip the little "choke" lever, wipe your thumb
across the electric-start button, and the engine is running.
The carburetors must contribute to yet another of
the KZ 400's attractive traits: its engine's willingness to pull fairly strongly
at low speeds. Smallish ports and mild valve timing helps, too, and it all comes
together to make a power curve that seems hardly to curve at all. Power rises
with revs, but smoothly and evenly, without being wobble-legged down near idle
or developing real biceps up at the red-line. It's an agreeable, unobtrusive
kind of performance from an agreeable an unobtrusive engine.
Techno-mavens won't find much inside the KZ 400's
engine/transmission casings to tickle their sliderule fancies. The crank is
carried in plain bearings, four of them, and the connecting rods also have
automotive-type inserts. A pair of sprockets located at the crank's center drive
chains running forward to the balancer and up between the cylinders to the
single overhead camshaft. The valve-actuating rockers pivot on eccentric
portions of their individual spindles and valve lash is set by rotating the
spindles until the stem-to-rocker clearance is right, then locking them in place
by tightening nuts located under the end-caps on the head.
The drive back to the clutch is across a pair of
special sprockets, held in place on their splined shafts by circlips, and a Hy-Vo
chain. This form of primary drive is more silent than gears, and has proven
exceedingly reliable in a similar application on all the Honda (500 and 350)
Fours. The Kawasaki KZ 400 probably will have the reliability; there's no doubt
about it being mechanically silent. There's very little noise from the primary
drive or transmission, and such as there may be gets submerged in the intake
honk set off every time the throttles are cranked open.
Kawasaki apparently has assumed that people who
buy the KZ 400 will do their own routine maintenance and has arranged things to
make such work easy. We've already mentioned the ease with which valve
clearances can be set; the same kind of thoughtfulness is evident elsewhere. You
don't even have to pull a dip-stick to check the oil level, because there's that
small sight-glass on the primary drive cover. A pointer on the rear brake
actuating arm gives an instant reading on lining wear and the owner's manual
tells you to replace the front brake pads when they have worn down to their
The engine has only a single set of ignition
points (its pistons move up and clown in unison, and the single twin-lead coil
delivers a waste spark on the exhaust stroke) so replacement and adjustment is
half as expensive and less than half as time-consuming as is true with twins
having 180-degree cranks and two sets of points. The oil filter is underneath
the engine/transmission casing but hasn't been made inaccessable by frame
members or exhaust pipes. And the rear wheel can be removed without disturbing
the drive sprocket, which is a big help when you're trying to fix a flat.
The engine's high-output oil pump is under a
cover located right behind the filter housing, and the cover has a cast-on boss
that looks ready to be drilled and tapped to take an oil-cooler fitting. We
think that's its purpose; we couldn't find anyone at Kawasaki who could
enlighten us on the matter. Still, it's an interesting point because our test
bike got very warm when flogged hard and might have benefited from having an oil
radiator to help it get rid of heat.
According to the experts, people who make
full-time use of the headlights on their motorcycles are less likely to be
picked off by cars. We'll concede that, but it still is annoying to find that
the KZ 400's 35/50-watt headlight is wired right into the ignition circuit,
lighting instantly when the key is switched to "ign." It strikes us as another
manifestation of creeping Big-Brotherism.
Plastics have become about as inevitable as
sunrise, and they are widely used in the KZ 400. The chain guard is a plastic
molding, and there's a secondary guard up inside the countershaft sprocket
housing that presumably serves to keep a broken chain from wadding up in there
and smashing the transmission casing.
The Kawasaki KZ 400 is handsome because it is
well-proportioned, and because—all the plastic notwithstanding—it is very well
finished. Kawasaki has in years past built a lot of bikes with chrome thinner
than the gold vapor-plated on a spaceman's faceshield, trowled-on welds and
paint you wouldn't put on a barn. There's none of that present on the KZ 400;
the bike looks really good.
Apart from the rear shocks, the things we liked
least about the KZ 400 was its handlebar grips. It's understandable that
Kawasaki would want their new model to have non-slip grips, but the only way the
KZ 400's could be made less likely to slip or less comfortable would be if they
were covered with spikes. The grips' ruffles and ridges will get to your hands
pretty quickly even through a pair of gloves, which is too bad because the bike
is in most other respects very comfortable.
The suspension isn't sufficiently refined to
provide a good ride, but the seating position is absolutely first rate. Some of
us felt that the seat would be better if it had another couple of inches in
width; all who rode the KZ 400 agreed that the seat/pegs/grips relationship was
The relationship between fuel tank capacity and
the availability of fuel was, in contrast, rather poor. The owner's manual says
the KZ 400's tank holds 3.7 gallons; we filled it right to the brim, let it
drain down through the lines into a graduated container, and had to shake the
tank for its last drops to get 3.1 after switching to reserve at the 2.7-gallon
mark. We think the bike's about a gallon short of having enough fuel for a
decent cruising range but then the energy crisis caught everyone by surprise.
Actually, just the 3 gallons is enough to take the KZ 400 at least 150 miles.
Even our test riders' customary forcefulness over the mountain roads near our
office was unable to depress the Kawasaki's mileage below 52 mpg, and a steady
55 mph cruising speed should bring it up close to 60 mpg.
That 60-mpg mileage figure will, for us, remain a
theoretical possibility—the KZ 400 was too much fun to ride fast to test for
fuel consumption at a steady 55 mph. Bad shocks or not, and even with the
braking deficiencies noted, we really enjoyed riding the Kawasaki hard. It is
one of the few motorcycles with enough cornering clearance to keep pipes and
stands up off the pavement, and even with the wheels blurring up and down on
their undamped springs the chassis' fundamental strengths make the bike safe and
Kawasaki will make much of the KZ 400's engine
balancer; people who ride the bike are likely, initially, to feel that the
reality doesn't quite live up to the advertising. It's an observable fact that
the KZ 400's balancer doesn't lend the bike the glassy smoothness of a Yamaha
TX500, but there's enough of a price differential to excuse the Kawasaki its
tremors. Also, the KZ 400 is a lot rougher when new than after a few hundred
miles have registered on the odometer and the engine parts develop into friends.
You'll get a high-frequency buzz cruising faster than 60 mph even after the
break-in period; the KZ 400 still is the smoothest thing in its
Basically the KZ 400 is like Honda's CB-360: an
updated replacement for the ultra-popular CB-350, and it's ironic that with both
Kawasaki and Honda building a replacement for one of Honda's motorcycles,
Kawasaki should have been more successful in capturing, and improving upon, the
essence of the original. Take away the Kawasaki KZ 400's wheel hop, firm up its
brakes and it would be a terrific motorcycle. With those ailments it's only what
its makers seem to have wanted it to be: a better, faster CB-350.
Source Cycle 1974
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