Kawasaki Z1-R: Into the R Zone

Kawasaki Z1-R
Years produced: 1978 and 1980
Claimed power: 90hp @ 8,000rpm
Top speed: 132mph (period test)
Engine type: 1,016cc air-cooled DOHC inline four
Weight (dry): 245kg (541lb) (563lb w/half full tank)
Price then: $3,695
Price now: $2,000-$5,000
MPG: 45 (avg.)

The 1970s produced the most dramatic transformation the motorcycle industry has seen before or since. The Kawasaki Z1-R proves the point.

In 1969, all street bikes were standards. Fairings were for race bikes. Twins dominated the big bike market. And “big” meant either a 650cc British bike or an overweight, underpowered 1,200cc V-twin from Milwaukee. Bikes leaked oil and were started with a kick; most small bikes were smoky 2-strokes and many needed pre-mix; wheels were wired, brakes were drums; and the “ton” (100mph) was a magic figure, often approached but rarely bettered.

A decade later, four Japanese manufacturers had a stranglehold on the industry, and their internecine competition (which to the public looked like sheer exuberance) had given the world fast, powerful motorcycles with three, four and even six cylinders, alloy wheels and triple disc brakes. They made close to 100hp/liter, and were capable of more than 130mph. You could park them in your living room without staining the carpet, and a simple push of a button spun the engine to smooth, purring life. The Superbike era was well and truly upon us.

But within a few short years, those easily jaded motorcycle journalists, instead of being astonished by these engineering marvels, casually grouped all Japanese bikes together with the prosaic abbreviation “UJM,” for Universal Japanese Motorcycle.

“King of the Road”

In the late Sixties, Japanese motorcycles were mostly small 2-stroke twins and singles or small 4-stroke twins from suck-squeeze-bang-blow devotee Honda. The first intimation that things were about to change came in late 1968 with the announcement of the Honda CB750 Four. At first, the competition stuck with their 2-strokes with the Kawasaki H1 and Kawasaki H2 triples, and Suzuki with the Suzuki Titan and Suzuki GT750, while Yamaha seemed to take more of a wait and see approach — though the Yamaha XS650 did give it a toehold in the big bike 4-stroke market.

Kawasaki was first to drop the other shoe. It’s widely reported that the K-men were working on their own single overhead cam 750 four under the project code name “New York Steak” when they heard about the new Honda. The design brief was subsequently altered to leapfrog Honda with an extra camshaft and another 150cc of capacity — there being no replacement for displacement, of course.

Though the final 1972 launch of the 903cc Kawasaki Z1 put it four years behind the Honda, the new Kawi was so much further advanced in performance that it created at least as much hoopla. With around 82hp on tap (compared with the Honda’s 60 or so), the Z1 ushered in a new age of performance. With 130mph capability, it was easily the fastest bike on the road. And it was also faster than its frame and cycle parts, as many early pilots found out.

Kawasaki’s H2 750 had earned a reputation for evil handling, and the Z1 continued that tradition. The mild steel double cradle frame lacked rigidity, the 36mm forks were under specified, and the rear suspension over sprung and under damped. To avoid a heavy steering feel, Kawasaki’s engineers also gave the Z1 a sharp 26-degree steering rake. Sudden changes of direction, encouraged by the quick steering, would induce weaves, which a few bumps could turn into a tank-slapper as the back wheel tried to catch the front. The single disc/drum brake combo wasn’t fully up to hauling 530-plus pounds of motorcycle down from 130mph, either.

Still, the Z1 was firmly established as the gold standard in the Superbike category, a position it held until 1977 when the Suzuki GS750 arrived. Kawasaki responded with the Kawasaki KZ1000; and in 1978, when the Yamaha XS1100, Suzuki GS1000 and Honda CBX had also joined the party, Kawasaki produced the Z1-R.

Radical Departure

The truth is, the Z-bike had seen relatively little development since its introduction. A second front brake disc was added in 1976, together with the designation Z900. The 903cc Z1 engine was then stretched to 1,016cc in 1977 by increasing the bore from 66mm to 70mm to create the KZ1000 — though claimed power output from the mille motor was still 82hp using 26mm Mikunis and a 4-into-2 exhaust. The KZ frame was beefed up with the addition of strengthening gussets, but it still lacked core rigidity.

Perhaps because of this, and because they were working with essentially a six-year-old motorcycle, the company chose to emphasize styling in creating the Kawasaki Z1-R. And while BMW and Ducati were first to fit factory fairings on the 1974 BMW R90S and 750SS, respectively, Kawasaki’s handlebar-mounted item on the Z1-R was the first on a mass-market Japanese bike. Its squared-off lines echoed the 3.4-gallon “coffin” gas tank, triangular side panels and swooping tailpiece — all finished in ice-blue metallic paint.

Behind the fairing was a neat instrument panel with matched tachometer and speedo, plus fuel gauge and ammeter. The Z1-R also introduced self-canceling turn signals, working on both a time and distance delay. The same KZ1000 engine (but with 28mm carbs) went into the same flexy-flier frame, and was hooked to a racy 4-into-1 exhaust. Claimed horsepower was up to 90 at the crank (though period dyno tests failed to find much more than the stock KZ). New cast alloy wheels were 18-inch front and rear, and drilled triple discs stopped the 541-pound missile.

The Z1-R’s radical (for the time) styling was a big hit, with the color especially causing something of a stir. Period testers either loved it or hated it, but almost no one was indifferent. Black had been the predominant color for Superbikes, so the R’s pastel paint was quite different.

“The R has what most bikes of its type do not — a styling theme, a common design theme which runs from one end of the bike to the other,” said Cycle Guide. “The R’s theme is straight sides and sharp corners, and the execution is with graceful, angular lines that flow so naturally from one area to the next that the bodywork sometimes appears to be all one piece.”

It was when reviewers actually rode the Z1-R that the wheels started to come off — off the ground, anyway.

The Z1-R used essentially the same frame as the KZ1000 (albeit with extra stiffening gussets), which was little changed from the earlier — and lighter — Z1. Kawasaki also fitted stylish new alloy wheels, the front now being 18 inches instead of 19. That reduced the already scant trail even more, making the R version livelier still than its predecessor. Add in stiffer rear springs and increased damping and you had a bike that was less than elegant on the move. “It doesn’t roll over bumps,” wrote Cycle Guide, “it bounces from crest to crest.” When it came to handling, the esteemed editors opined, the Z1-R’s “numerous rubbery frame tubes” and flawed suspension setup allowed the Kawasaki to “ride harshly on the flat and … wobble in fast turns.”

In a November 1978 shootout between the Z1-R, Honda CBX, Suzuki GS1000S and Yamaha XS1100, the Z1-R trailed in just about every test: the CBX blitzed it on the drag strip, the GS1000 thrashed it on the track through its superior handling, and the XS1100 was far more comfortable. In just six years since the Z1 had been introduced the competition hadn’t only caught up, it had moved on.

Z1-R Revisited

Chastened perhaps, Kawasaki dropped the Z1-R for 1979 before returning in 1980 with a significantly revised version that seemed to meet much of the criticism leveled at the 1978 model. Gone was the metallic silver-blue paint and 4-into-1 exhaust system, and the frame had been tossed in the dumpster. Replacing it was a new, stiffer chassis with double-walled down tubes from the 1979 KZ1000 “MkII.” The penalty was a weight increase to 552 pounds dry.

The new frame, together with a 19-inch front wheel and reduced offset in the triple clamps, increased trail from 3.3 inches to 4 inches. The wobbles, harsh ride and choppy handling of the 1978, were contained, though the new bike still compared less than favorably with the GS1000S in this respect. In the engine, a new, heavier crankshaft with revised balance factor reduced vibration, but the overall specification remained the same. A more practical 4.4-gallon (plus reserve) gas tank replaced the 3.4-gallon item from 1978, and a more comfortable seat increased the rider’s range to match that of the bike.

Read Aki Shinohara’s experience of owning and riding a 1978 Kawasaki Z1-R

Other detail changes included high-speed V-rated tires, a 2-tooth reduction on the rear sprocket for snappier acceleration, and improved ground clearance. The only available finish was black.

One curious feature was the front brake operation, achieved via a cable leading from the lever to a remote master cylinder (BMW used a similar setup on its late 1970s and early 1980s R-bikes). This gave an indirect feel to the lever which, ironically, was panned for being vague and praised for moderating the front brake’s “wooden” feel. Reviewers still found the GS1000S quicker on the track, but the Z1-R’s new lower gearing meant it was quicker on the drag strip, where it proved its mettle time and again.

The Z1-R had finally grown up: Kawasaki’s engineers had tamed the beast so it would still do the business when the tree lights turned green, but was far less likely to bite you in the bends. Much of this development went into the green team’s AMA racing challenge in 1981, when one Eddie Lawson ended the season in first place. In celebration, Kawasaki produced one of the most evocative bikes of the era, the KZ1000R Eddie Lawson Replica, which extended the model for yet another few years, into 1983.

With a particularly stout engine and superb styling, Kawasaki’s 1978 Z1-R should have been a runaway success. But most found it too much of a handful to make the most of its potential performance.

So does it deserve to be a classic? As the motorcycle that contributed so much toward the KZ1000R, we’d say there’s no question. MC

Press Reports

“They can call this bike what they want … but it’s a Z, and it acts like a Z, and it feels like a Z. You know what that means: fast, tough and a trifle crude. Just the way we like it.”
— Cycle, December 1977

“Handling is on a par with the engine. In fact, one could say the handling is like the engine: both work well within certain limits.” — Cycle World, December 1977

“The Z1-R can exceed any U.S. speed limit in first gear, and it can get past the magic 100mph mark in third. Our bike did the standing-start quarter mile in 12.13 seconds at 109.6mph, making it second only to the Yamaha 1100 on the list of all-time fastest accelerators.” — Cycle Guide, January 1978

“The bike has enough raw horsepower to be truly impressive on the straights, but the first rule of handling for a 90hp motorcycle is to give it a 90hp chassis, and that is something the Z1-R doesn’t have.”
— Cycle Guide, January 1978

“The Kawasaki is very predictable about its wobbles. They’re always low in frequency, and they don’t get much worse as the speed increases.”
— Cycle Guide, November 1978

“There’s no question the speed-styled Z1-R offers you more thrills and more comfort than ever before. Image bikes like this one have to offer you a lot more, too, to justify premium prices.”
— Cycle World, April 1980

“Kawasaki’s new Z1-R isn’t the same motorcycle at all. It functions with the same grace as the current KZ1000, proving that a bike doesn’t have to be nasty to deserve a high-performance image.”
— Cycle World, April 1980