Four stroke, transverse four
cylinder, DOHC, 2 valve per cylinder.
903 cc / 55.1 cu-in
Bore x Stroke
66 x 66 mm
Wet sump, trachoid pump
Treated synthetic fiber
4 x 28mm Mikuni VM28SC
Battery and coil
Electric & kick
82 hp / 59.8 kW @ 8500 rpm
73.5 Nm / 54.3 lb/ft @ 7000 rpm
Straight cut gears
1st 12.79:1 2nd 8.84:1 3rd 6.74:1 4th 5.58:1 5th 4.92:1
Double tubular steel cradle
36mm Telescopic forks
Dual shock, 5-way preload adjustment
Single 296mm disc 2 piston caliper
Length 2209.8 mm / 87.0 in.
1498.6 mm / 59.0 in
818 mm / 32.2 in.
812.8 mm / 32.0 in.
170 mm / 6.75 in.
230 kg / 507 lbs
247.6 kg / 546 lbs
18 Litres / 4.7 gal
Braking Distance 30 mph - 0
Braking Distance 60 mph - 0
Acceleration 0-30 mph
Acceleration 0-60 mph
12.3 sec / 112 mph
FRAME NUMBER: Z1F-020001 >
ENGINE NUMBER: Z1E-020001 >
COLOUR: CANDYTONE BROWN/ORANGE OR CANDYTONE GREEN/YELLOW
Major changes for this model were the silver engine finish, redesigned tank
and tailpiece markings and a stop lamp failure light in the tachometer. The
idiot light cover was also changed, the warning lights were now placed in a
different order. The best gets better.
FRAME NUMBER: Z1F-047500 >
ENGINE NUMBER: Z1E- 047500 >
COLOUR: CANDY SUPER BLUE OR CANDY SUPER RED
Major changes for this model were paintwork and markings, larger side panel
badges and the adoption of an 'O' ring chain instead of the previous built
in chain oiler. The switchgear was slightly cosmetically changed and the
Speedo was now in 10-mph increments. The fuel tap was changed from black to
silver and the carbs were modified to improve performance.
After the revolution Honda CB 750, it was in 1972
that Kawasaki lays first brick of the race for power with its Z900. It is
immediately a success that the machine confirms its reliability, both in
everyday life than on circuits.
Compared to the Honda CB 750, it provides a larger engine thus more power (82
hp instead of 67), and more torque and argument, dual overhead camshafts.
While keeping the 4 exhaust pipes traditional at the time (the devil pounds),
it has a look of hell, especially in color Tobacco with its orange flames and
black engine mat. The cooling fins of the breech but keep a sharp color
aluminum. This dress will be taken over by the 750 Zéphir at its latest
development. For practicality, the chain is lubricated from an oil tank
located under the seat in the left side of the frame.
The machine will be distributed from 1972 to 1976 and each year suffer a
slight change. In 1974, 900 Z1A is distributed with a new decoration (less
beautiful than the original) and the engine loses its matte black paint. In
1975, technology evolves, the machine (Z1B) comes with a chain to O-rings,
where abandoned oil pump. In 1976, the machine (A4 series) is now shipped
standard with dual front disc.
In 1977, the machine disappears from the catalog of the manufacturer, victim
of the war to the power it has triggered. It is replaced by the Z1000.
The Z1 Chronicles
Kawasaki’s 900 Super Four Z1 did more than blow past
Honda’s CB750 in terms of performance, refinement and all-around ability.
It was the world’s first superbike.
"A velvet blunderbuss, and every inch a King."—Cycle,
For just a moment, imagine you're Kawasaki's Sam
Tanegashima in the fall of 1968. As a project leader you've been slaving
night and day for the better part of two years on what was then internally
known as N600. It is going to be a groundbreaking road-burner that will
become the most important motorcycle in the world, with a contemporary
mass-production first of an air-cooled, DOHC, 750cc inline-four. Testing is
all but complete and has gone swimmingly—your finger is metaphorically
poised to push the button to begin production early next year. You might
even allow yourself to think life is going to be very, very good.
And then you get the phone call from the 1968 Tokyo Motor Show. It seems
competitor Honda had the same idea—only a bit sooner—and has knocked
motorcycling on its ear with the revolutionary CB750 Four. Suddenly there is
indeed a new most important motorcycle in the world—but it ain't yours.
Shame and frustration taste more acrid than bile. One remembers it with
So it was for Kawasaki's N600 project team as they returned to Akashi to
lick their wounds—and vowed to kick Honda's ass from Tokyo to Tucumcari to
Turin and back by building something bigger, faster and even more
sophisticated—a true King of Motorcycling. It would take the better part of
four years, an eternity compared with current two-year product cycles for
today's 600cc and 1000cc sportbikes. But Kawasaki was determined to get it
At the time Kawasaki was in the midst of changing its entire approach to
building motorcycles. As Tanegashima says in Micky Hesse's book Z1 Kawasaki,
"One motto [we had] for developing the Z1 was to create one piece of
motorcycle. Before the Z1, Kawasaki had developed several very fast
motorcycles like the A7, H1 and H2. It was not sure if we were selling
engine/horsepower or motorcycle.
"From the very beginning of Z1 development," he says, "we made sure to
develop one piece of motorcycle, not independent engine or chassis or
Tanegashima added that the Japanese were well known for their me-too
approach—going along to get along, so to speak. "Our people tend to like to
do the same thing as [their] neighbor. In product development, this tendency
leads to [copying] some competitors or leaders. However, [our] motto in
developing the Z1 was to make it completely different from Honda's CB750.
This [is] a very rare case in Japanese society."
Equally interesting is a passage from Kawasaki's museum Web site (www.khi.co.jp/mcycle/museum/index_e):
"[With the Z1] Kawasaki changed their engine design policy so that the
powerband was not set near the engine's [rev] limit, thereby pursuing
elegance and smooth engine performance." At its heart, that change stemmed
from Kawasaki's decision to substitute four-stroke powerplants for
two-strokes in making top-of-the-line models. After all, Kawasaki had in
1963 absorbed Meguro, one of Japan's oldest motorcycle manufacturers and
known for its four-strokes, so Kawasaki had four-stroke engineering
expertise. (To this day, the firm still uses Meguro's logo on packaging and
signage.) Indeed, Kawasaki's talented engineer Ben Inamura had already
developed the firm's previous foray into four-strokes, the BSA-like 650cc
W1, from a Meguro 500cc K2 vertical twin. And it was Inamura who would
become the project leader for Kawasaki's N600 750cc engine and then for the
Z1's 903cc powerplant.
Still, the question came up at the Z1's model-introduction press conference
in the fall of 1972: Why was Kawasaki seemingly abandoning its two-stroke
heritage to create this four-stroke? In Cycle magazine's road test of the Z1
in the November 1972 issue, Kawasaki's Motorcycle Division General Manager
T. Yamada's response was cited: "Lots of reasons, he said. Kawasaki wanted
to build, in their words, the King Motorcycle, a bike beside which the
finest motorcycles in the world would shrivel in comparison . . . a bike
that would leave a hot and smoking scar across the face of the sport . . .
And you just can't do it, Yamada was saying, with a two-stroke engine . . .
In the first place, Yamada said, the King Motorcycle must have an engine
that sounds right.
"No less important, said Yamada, is the way the engine looks. Who could
imagine a King Motorcycle with an engine that looked like a two-stroke
engine looks, all crankcases and cooling fins? The King . . . has to have an
engine that looks impressive. And only a big four-stroke is right."
Another important consideration at the time was the greening of America—in
the face of rising vehicle emissions. Even in 1972 it was obvious that
stinkWheel-powered motorcycles were living on borrowed time. Besides this,
Kawasaki had already done massive amounts of focus-group research that
clearly indicated a big, four-stroke-powered road burner was absolutely
right for the intended audience—primarily U.S. riders—and for the times.
Nonetheless, it's vitally important to remember Kawasaki developed the
two-stroke 500 Mach III concurrently with the stillborn 750. That gave the
company an exceedingly high-performance motorcycle to sell as it tested,
retested and refined the Z1, which had its code name changed to T103 in
1968, then changed again later to 0030; final prototypes were designated
9057. Perhaps the most famous code name/internal reference was New York
Steak, although one wonders, given Kawasaki's desire to create the ultimate
King of Motorcycles, that someone didn't dub it Filet Mignon or even
Even if it were to be known as Montmorency, Kawasaki was taking no chances
whatsoever with the Z1's program of testing and refinement. For example, a
gaggle of 9057s were shipped to the U.S. in February 1972, where two teams
flogged the horns off the poor, unsuspecting prototypes. Bryon Farnsworth,
Kawasaki America's senior test rider, was joined at Willow Springs and at
Talladega Superspeedway by the company's race team, including Gary Nixon,
Paul Smart and Hurley Wilvert, who cheerfully abused the remarkably stoic
motorcycles. On Talladega's 2.66-mile tri-oval course, they ran the bikes
WFO for the time it took to drain the 4.7-gallon fuel tanks. Testers also
ran some 5000 miles on real roads in this country, going
coast-to-coast-to-coast, Los Angeles to Daytona Beach and back. After so
much development on dynos, roads and racetracks, the only even slightly
unseemly trait the Z1 demonstrated was an apparent appetite for rear tires
and final-drive chains, consuming the former in about 6000 miles, the latter
in roughly half that distance.
Farnsworth had been working for Cycle magazine when he was approached by
Kawasaki to take on the role of senior U.S. test rider, specifically for Z1
development. "I was the first round-eye to ride the Z1," Farnsworth says,
"and I was the only American to go over to Japan to test the bike."
So in 1971 Farnsworth was sent to Japan. Initial plans called for riding the
bike around the vast, 3.4-mile banked oval of the MITA test track, but those
plans fell through. Kawasaki then found a parking lot and threw out some
cones to create an impromptu "handling circuit."
Farnsworth, who figured he was being paid to tell his employers the truth
with no sugarcoating whatsoever, did so. "The bike immediately started
dragging its mufflers around corners," he says. "I told them it was a rakuta,
or water buffalo in Japanese." Eventually the testing team made it to a real
track, Tsukuba circuit, but even that was short—just over a mile long—and
not really suited for wringing out the King of Motorcycles.
See, at this point in the Z1's development, Kawasaki was deeply concerned
about the bike's durability and reliability, and rightfully so. Such
problems could have not only scuttled the Z1 in the marketplace, but they
could have sunk Kawasaki's reputation as well. Of course Farnsworth knew
just where to go—Talladega Superspeedway. So in late 1972 the entire
Kawasaki Z1–testing entourage descended on Talladega, which they'd rented
for 30 days.
"They were holding it wide open for an entire tank of gas," Farnsworth says,
"doing about 140 miles per hour." Nothing of consequence broke, but this was
back in the day, before manufacturers learned something about shock damping
and frame stiffness. "It was a wiggler at the time," he says, "but only if
you let off. If you had the balls and held it wide open, it was OK.
"It took about 10 years for them [Kawasaki, and other manufacturers] to
figure out the steering head was connected to the swingarm pivot and that
you can't put an engine in there that's going to try to twist the frame
As a side note, Farnsworth mentions that the Japanese engineers tended to
hang out together—especially at the hotel at night, after testing was done.
No big deal, right? Except that they were squatting down in a big circle
drinking beer outside a hotel—in the South. Alabama, to be precise. So of
course the Heat swooped in and carted them all off to jail, and Farnsworth
had to bail them out.
But that's not all. From March 13 through 15, 1973 (after the Daytona 200
had run), Farnsworth brought a full-factory assault team to beat Suzuki's
record set in 1968 of running 90.11 mph for 2172 miles. Included were
Kawasaki's American roadrace team riders of the day—Yvon Duhamel, Art
Baumann and Gary Nixon, among others—and several U.S. moto-magazine editors,
including Cook Neilson of Cycle and Motorcyclist's own Art Friedman.
Ultimately they slaughtered Suzuki's record, posting a new one of 109.641
mph for 2631 miles. A special one-off Z1 tuned by Yoshimura and ridden by
Yvon Duhamel set a new record of 160.288 for one lap.
So what was this King of Motorcycles? How was it configured? What was it
From the beginning, the Z was always all about its overachieving powerplant.
Kawasaki claimed 80 horsepower for the air-cooled, transverse
inline-four—handily about 15 bhp more than Honda's CB750. Cycle's test
described it this way: "Horsepower flows . . . like water from an Artesian
well. It simply never stops."
To further distance the Z1 from the CB750, the Z utilized square bore x
stroke dimensions of 66 x 66mm, rather than the Honda's old-school
long-stroke numbers, to get 903cc of displacement. When asked why, Kawasaki
answered with a shrug, saying, "That's all it needs." This was a very early
indication that the Japanese manufacturers were no longer interested in
archaic, rigid and limiting class displacements. A sophisticated DOHC
induction system (still rare on mass-production bikes, if not on Euro
performance cars) was fed by a bank of four 28mm carbs.
Down in the crankcases lived a nine-piece, pressed-up, roller-bearing crank,
with caged needle-rollers for each con rod to ride on —evidence enough of
Kawasaki's massive two-stroke design background. Sufficiently impressive,
apparently, for Cycle to write, "The lower end looks like it came out of a
Porsche Carrera." Power then transferred to a massive, wet, multiplate
clutch and to an equally overbuilt five-speed transmission. This strength
would serve the bike well on the streets, racetracks and dragstrips of the
world for many, many years.
Although the DOHC system with its shim adjusters was slightly more complex
than the screw-and-locknut adjusters of most other bikes, Kawasaki tried to
make amends by keeping other maintenance procedures as simple as possible.
As a result, any major top-end wrenching that might be required could be
done with the engine still in the frame.
Where Kawasaki really made a breakthrough, however, was in emissions
control. For instance, sintered valve seats made them impervious to unleaded
fuel, while a low, 8.5:1 compression ratio ensured the Z's mega-motor could
run on the wateriest swill pumped anywhere in the U.S. More important,
though, was the crankcase fumes rebreather. A canister on top of the cases
and behind the cylinders separated oil from blow-by, then routed the fumes
to the airbox. Absurdly simple, but a scheme claimed to reduce hydrocarbon
emissions a full 40 percent.
By comparison, much of the rest of the motorcycle seemed, well,
conventional. Yes, the stylists managed to make the big Zed appear slimmer
and more lithe than Honda's four-cylinder, but to quote Cycle once more:
"The bike's styling is conservative by normal standards, and positively
funereal by Kawasaki's, the company that gave the sport laser stripes and
lollipop paint jobs!"
Others, though, felt the Zed was eminently more lustworthy than the CB750—or
any other motorcycle, for that matter. Such considerations, along with the
Kawasaki's crushing performance advantage, made the bike a smash hit with a
bullet when it hit U.S. dealers' floors in November 1972. Likewise, the
press was just as bowled over.
"The thing that impresses you about the 900 is its great straight-line
stability at very high speeds. We could cruise at 120 mph sitting bolt
upright." —Cycle Guide, October 1972
"The Kawasaki 903 Z1 is the most modern motorcycle in the world. It is
also the fastest. It is above all the first of a new generation of bikes, a
generation which will run quietly on the streets of America, a generation
which will attempt to solve motorcycles' tiny contribution to the world's
dirty air; it is the first of a generation of motorcycles which will come
close to being within reason all things to all people, capable of nattering
down quiet country roads packing double one minute and rotating the Earth
with incomprehensible acceleration the next." —Cycle, November 1972
"The Z1 is one of those shockingly understated GT machines, the kind on
which you can look down at the speedometer and discover, 'My God, I'm doing
90, I'd better shut down.'"
—Cycle World, March 1973
"A Z1 is the only bike left to which those famous lines from a mid-'60s
road test on a Harley Sportster still apply: 'It will make hair grow on your
chest, and if you've already got it, it will part it down the middle.' "
". . . the first 903 Z1 four-cylinder had velveteen refinement and enough
performance to place the most refined gentleman in a state of serious
sweat." —Cycle, May 1987
" . . . Kawasaki, like a black-sheep uncle, has never failed
to pat us bad-boyishly on the head, give us a surreptitious snort from a
hidden flask, and affirm our suspicion that life without suspense is no life
—Cycle World, April 1993
In short, Kawasaki's 900 Super Four Z1, as it finally came to be known, was
a revelation, a motorcycle that pointed the way to the future for virtually
every other manufacturer on the globe. The direction was definitely toward
performance, but it wasn't the harsh, demanding type that characterized
Kawasaki two-strokes such as the Mach III and Avenger. Instead, it was a
kinder, more civilized performance—but at an even higher level—and as
inviting and inclusive as the two-strokes felt hostile and divisive to some.
Even so, the Z1 didn't quite generate the all-inclusive, big-tent appeal of
Honda's CB750. There was still just a bit of an edge, a subtle feeling of Us
versus Them. Where the CB750 had this wonderful malleable quality that
allowed it to accommodate whatever role the owner had in mind, the Z1 wasn't
quite as obsequious. It's not that the bike wasn't capable of such
shape-shifting; it's just that the Z1's performance (especially the
engine's) was so inviting and user-friendly.
Such qualities guaranteed Kawasaki's Z1 would be remembered as the
motorcycle that ushered in the Superbike era—and cemented its place in