1974 Kawasaki KZ400 Commuter Special - 6-Page Vintage Motorcycle Article

Description

1974 Kawasaki KZ400 Commuter Special - 6-Page Vintage Motorcycle Article
Original, vintage magazine article.
Page Size: Approx. 8" x 11" (21 cm x 28 cm) each page
Condition: Good
KAWASAKI KZ400
COMMUTER SPECIAL
The idea might be a copy, but the finished product is an original
Timing. That's what it’s all about. More
often than not, the success or failure of
a particular product not only depends
upon its inherent quality and price, but
upon the time at which it is presented to
the public as well.
When Kawasaki introduced their all-
new KZ400 in early 1974, their timing
couldn't have been better. There the world
was. right smack dab in the middle of an
energy crisis, its people desperately
searching for new ways to get around
without consuming large quantities of that
precious, costly commodity, gasoline..
In the ensuing confusion that reigned,
some of those people discovered that mo-
torcycles are a very economical means of
commuting. They learned that bikes are
relatively inexpensive to purchase, use
only a fraction of the fuel gulped by their
gluttonous four-wheeled counterparts, and
can thread their way through a traffic jam
like a pro halfback through a high school
defensive line. And to lop it off, they
found you can park a small fleet of the
little buggers on the same piece of acreage
required to house one large economy size
American luxury car.
But most of these new buyers weren’t
usual, run-of-the-mill bikers. They weren't
looking for a new hobby that would lake
up a lol of their free time with tinkering
and tuning. Their decision to buy was not
motivated by quarler-mile times or lean
angles or lop speed. And they could really
care less about gadgets—things like vac-
uum-operated turn signals or sonar curb
feelers or any of that exotica. All they
wanted was something that would lake
them from point A to point B while
requiring a minimum of feeding—and
that’s it—no more, no less.
Ironically. Kawasaki was pulling the
finishing touches on the KZ400 just about
the lime the “crisis” got into full swing.
The bike had been conceived long before
the crisis had been conceived, but none-
theless. the KZ was tailor-made for the
situation. It had not been specifically de-
signed for the performance-minded en-
thusiast, but rather for those persons in-
terested in economy, reliability, smooth-
ness, and ease of operation. It was in-
tended to provide most of the advantages
of small bikes, but without the disadvan-
tages that normally accompany little ma-
chines, And on top of all that, the KZ400
had good timing. So. capitalizing on the
state of then-current events. Kawasaki
dubbed the KZ400 “The Commuter Spe-
cial.”
Too. Kawasaki surely wanted the
KZ400 to have a little sporting blood
flowing through its frame tubes, but not
at the great expense of all that no-non-
sense stuff. So they supplemented the
fundamentals with a sprinkling of mild
gadgetry—the type that wouldn’t scare the
New Buyer away, but could possibly catch
the fancy of the Old Standbys. The bike
isn’t revolutionary in any way. but it com-
bines several ideas that have been around
in various other machines and blends
PHOTOGRAPHY BY ART FRIEDMAN
them together to form a rather unique
motorcycle.
THE BIKE: The four-stroke twin-
cylinder engine looks quite a bit like the
one in the Honda CB360 (formerly
CB35O). which is probably the most pop-
ular street bike of all time. Actually, the
whole motorcycle looks a lot like the 350.
because Kawasaki patterned the KZ400
after the CB350. There was one year in
which the 350 series Hondas outsold all
Kawasakis put together. Yet. until the
KZ400, no other Japanese manufacturer
had tried to market a bike that would be
in direct competition with the 350. When
a motorcycle has had the unopposed, un-
qualified success of the Honda 350, it
shows good sense to be the first company
to build a copy.
Like the 350. the KZ400 has a chain-
driven single overhead camshaft, with ec-
centric rocker spindles for valve lash ad-
justment. The 64mm bore and 62mm
stroke yield 398.9cc, and a 9 to 1 compres-
sion ratio allows the use of low-lead or
unleaded fuel.
Balance lubes between exhaust pipes
are quite common, but instead of an ex-
ternal pipe, the KZ400 has an exhaust
balance tunnel built right into the cylinder
block and head. The crossover doesn't
leak, and you can’t even tell it's there,
which eliminates some unsightly plumb-
ing al the front of the engine.
The KZ400 uses a 360-degree crank-
shaft. which moves the pistons up and
down together, firing alternate cylinders
on each revolution. Kawasaki chose this
arrangement over the CB35O-lype 180-
degree crank for several reasons. They
knew that the 360-degree crank causes
more high-rpm vibrations than the 180-
degree setup (which has one piston going
up while the other is going down), because
the 180 crank lets one piston’s movement
partially cancel the other piston’s move-
ment. But at the same time, the 180 does
not let the engine run quite as smoothly
at low rpm because the firing impulses
are unevenly spaced. The first two firings
are 180 degrees apart, then the next one
comes 540 degrees later. Since the KZ400
was designed primarily for commuting at
low rpm rather than play-racing at higher
rpm. Kawasaki's engineers choose the
360-degree crank. They also added a pair
of chain-driven balance counterweights
(like Yamaha’s Omni-Phase balancers),
one just in front of the crankshaft and
one just to the rear. With this arrangement
Kawasaki’s designers felt the 360-degree
crank would provide smooth lugging al
low rpm. while the balancers would cancel
most of the high-rpm vibrations.
However, mounting one of the bal-
ancers just behind the crankshaft means
that the distance from the crank to the
five-speed gearbox must be unusually
longMoo long to use gears as a means
of primary drive. A pair of gears big
enough to span that crankshaft-to-
mainshaft distance would be prohibitively
large. So, Kawasaki chose a chained pri-
mary drive, using the gear-type silent
chain. The Honda CB500 pioneered the
use of this chain on production motorcy-
cles, but it has been in use for years in
automobiles and as a substitute primary
drive for the powerful 750 Triumph and
BSA twins racing the AMA national cir-
cuit.
Using a chained primary drive and...
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