Kawasaki's Muscular Monarch

The year 1967 was awash in monumental events. Summer of Love bromides aside, the image of Hendrix immolating his Strat at Monterey is a visual time stamp of a convulsive year. Change and upheaval, among other things, were in the air. In the world of motorcycle design, a revolution began gestating under the radar that would rumble the cycle culture like a stack of 100-watt Marshall amps. Sam Tanegashima, Kawasaki’s double-naught engineer, began work on the cryptically designated “New York Steak” project. Tanegashima’s mission was to craft a visionary super-cruiser, a powerful bike that would ease comfortably through urban traffic, yet be capable of grinding pavement into grit on the open road. The Z1 was to be an indomitable Goliath before which all others would wither, a “King Motorcycle”, in the words of Kawasaki.

The New York Steak project labored through ’67 and into ’68, designing a four-stroke, four-cylinder engine. While Kawasaki was known primarily as a two-stroke manufacturer that had done quite well with its performance-oriented two-strokes, tightening EPA regulations hung over that technology like an inversion layer. In 1963, Kawasaki had acquired Japan’s oldest motorcycle works, the Meguro factory, whose four-stroke production ability helped put the ambitious N.Y. Steak plans on Kawasaki’s front burner.

The road to innovation is a perilous one, and for a while it looked as though Kawasaki’s revolution would not be televised. In October 1968, Honda dropped a four-cylinder bomb of its own at the Tokyo Motor Show, the knockout CB750KO, beating Kawasaki to the punch. As Honda’s October Surprise was being unveiled across the Pacific, the rudimentary mock up of the twin-cam Z1 sat in Sam Tanegashima’s West Coast studio apartment. A Teletype issued the dire news, “…drastic review on our product inevitable.” (Click image to enlarge)

Dazed, but not confused, by Honda’s suckerpunch, Kawasaki regrouped and assembled a design team in April 1970 to focus on the redeveloped Z1. While seeking to avoid also-ran status in the wake of the CB’s ambush, Kawasaki held fast to the Z1’s basic constitution. The bike would remain a four cylinder and employ a disc brake. The bike would handle well and be emissions friendly. Most importantly, the Z1 would eat the CB750 alive and floss with its spokes.

In early 1972, test bikes were sent to the U.S. for the express purpose of being beaten within an inch of their lives by a ballsy gang of Kawasaki leathernecks, and beat them they did. Post-mayhem teardowns at Kawasaki’s California outpost revealed the Z1 was good to go. Kawasaki’s reinvigorated efforts were about to pay off.

Euro-spec dual discs grace the front wheel. (Click image to enlarge)

In 1973, the new kid on the block was a 903cc menace to society that would scatter street football games and send sidewalk surfers diving off clay wheels into hedges. With brutish, swooping lines and quad pipes clutching a magnificent engine like a black heart in an iron fist, the Z1 was an archetype of menacing style. Natty in its distinctive candy tone brown/orange color scheme, the big Kawasaki looked like a heavyweight boxer out for a night on the town in a root beer suit.

The impact was immediate. The big Z won hearts and minds in the press and on the street. Nothing like it had ever been seen before. Kawasaki began rolling Zs off the line at rate of 1,500 per month. At $1,895 ($8,400 in today’s dollars), they disappeared so fast that even Kawasaki employees couldn’t bag them through the employee discount program. Sales surpassed the CB750, whose conservative styling had begun to grow grey at the temples by 1973. There wasn’t much else in the way of competition for the Z1. No other bike came close to the power, reliability and brute style offered by the world’s newly reigning superbike. The Z1’s introduction would retune Kawasaki’s image from a producer of smoke-belching two-stroke triples to a builder of muscular, sophisticated four-stroke motorcycles. The Zed was the alpha bike and the road lay open before it.


Upright was the sport standard in 1976.

The focus of the adulation heaped on the Z1 was the mouthwatering 66mm x 66mm 903cc engine. If reasonable men can describe a block of metal and chrome pipes as sexy, the Z’s powerplant was a dual-cam Raquel Welch. With black-finished castings, polished side covers and chrome accents, the Z’s motor was unlike anything previously seen on a production bike. The engine leans eagerly forward into the downward sweep of the beefy exhaust pipes to create room for the quartet of Mikuni carburetors mounted behind. Kawasaki’s designers were insistent that the engine look impressive from the Z1’s inception. Their exertions to that end paid off handsomely. Big and wide, the motor was designed to accomplish a lot with little effort. On that count, as well, it was a success. The Steak’s double overhead camshafts push the protein directly to the valve stems without meddlesome rockers or pushrods getting in the way. The original Z1 engine put out 82 hp @ 8,500 rpm, which it was capable of sustaining over long stretches without roasting the innards. This was in an era when 50 horses was a considerable stable. Kawasaki realized that while most American riders might not ever use that much brawn, they wanted to know it was available.

The Z1 went through minor permutations through the ensuing years. In ’74, the Z1 was rechristened the Z1B. The update featured crank balance alterations to add a layer of smooth, while ignition and jetting alterations improved off-idle response. Cosmetically, the B featured the now-familiar striped paint scheme and abandoned the black cylinder block and head in favor of a polished alloy gleam. The ’75 Z1B’s song remained the same, save for a blue or burgundy based color striping. That year, the Z1-P was conscripted into service by law enforcement, as many well-ticketed veterans would surely like to forget. The original generation of  Z bikes ended in 1975.

The next year, Kawasaki retagged the bike KZ900, and while it was much the same machine as its Z1 predacessors, the bicentennial edition featured some modest changes. Tuning alterations and smaller carbs shaved a few watts off the powerplant in an effort to refine the bike’s raw grunt, but riding a KZ900 today precipitates a case of adult-onset deja vroom.


Timeless refined excellence.

This bottle green KZ, beautifully restored and upgraded by Redline Cycle Service of Skokie, Illinois, is deceptively quiet, producing a spirited rustle at idle. The raised bars and stepped saddle, combined with a long, low-slung tank, give the rider the impression of being perched atop the bike, rather than settling down into it. The classic angled clocks are easily read, and while the KZ is outfitted with the standard array of idiot lights, the alarming red “STOP” lamp that glows brightly whenever the brakes are used might have modern riders threatening to yank some cables. Pulling away from the curb, the CV carbs cause a little engine hiccup without a good handful of the rangy throttle—a throttle that requires a full turn and a half of the wrist from the non-double-jointed to fully open the four mouths. The clutch and gear changes are agreeably smooth, but the occasional false neutral will plague those not sure of foot.

Just as intended, the KZ900 engine burbles smoothly through traffic in the 3,000 rpm range without much gear changing, although the occasional downshift will goose the bike along nicely. Revs rise and fall slowly, and at 72 hp (10 fewer than the ’73 Z1) the KZ900 is sufficiently powerful, without being overwhelming. Today’s rider might find the engine and CV carbs a bit sluggish, but considering the 30-year-old technology through the prism of history, it was remarkable for it’s time—so remarkable in fact that the 1976 KZ900 wrangled “best roadster in its class” honors from Cycle World magazine at the time.

If the KZ is a low-torque Jekyll in the city, getting it out of town unleashes its inner Hyde. The bike redlines at 10,500 rpm, but the beast doesn’t truly sprout fur until about 6,000. Running the bike up the rev ladder will complete the flashback sequence in the rider’s mind. The engine opens up with familiar punch and that unmistakable burbling exhaust note creeps up from behind.

The bike is nicely balanced and, when outfitted with modern bias-belted Bridgestone rubber, won’t flop into corners, nor is it reluctant to lean in to turns. Occasionally, road undulations will induce the Z’s well-documented high-speed wobble. Likewise, if you push it hard enough, you can grind the center stand, though overall ground clearance is usually adequate. As it did back in the day, top gear doesn’t seem as tall as it should; when cruising, you’ll possibly find yourself reaching for a phantom overdrive. The rubberized foot pegs are properly positioned and help damp the already-acceptable amount of engine vibration. The KZ, big for its day, doesn’t feel particularly heavy or cumbersome in comparison to modern bikes. Overall handling and rideability are remarkably obliging, a nod to the Z designers’ intent to build a large, powerful bike that handled well. The Euro-style double disc front brakes (an option here in the States) have ample bite and feel. Likewise, the progressive rear drum lever has an abundance of travel but inspires confidence when you put your foot down.

The KZ900 was the last of the Z900 breed. In ’77, Kawasaki boosted the displacement to 1015cc, increased the weight, and further civilized the bike. The ’76 KZ900, like a bottle-green Polaroid, certainly is time-specific. So, if you are looking for a two-wheeled way-back machine capable of quiet wayfaring one minute and pavement unraveling acceleration the next, slip a hairbrush in the back pocket of your flares, snap on your puka shells and dig up your Frampton Comes Alive! eight-track...actually, this is a Z. Better make it the Ramones.