Three is Not a Crowd: 1978 Kawasaki Z1-R

Injured in the military and medically retired, Trace fretted about the amount of time it was taking to recuperate. Rehab went a lot better after he found a second 1978 Z1-R that had been in a rear end collision. Trace built up his second Z1-R into an AMA Ultra Stock drag racer, prepped to be just barely legal for this class. It is bored out “one step over,” and has higher compression pistons, a longer swingarm, a plugged front end and wire wheels, front and rear. Weight has been shaved in every place possible. It now turns the quarter-mile in 9.3 seconds with a terminal speed of 140mph. “The ZI-R has a powerful engine, and it’s rock solid. I’m using the stock transmission except for second gear. The stock transmission is good up to 160mph and seven second times, then you have to go aftermarket.”

Beginnings

The Z1-R was a direct descendant of the 1972 900cc Z1, Kawasaki’s answer to the Honda 750 Four. The Z1 had double overhead cams, an unbreakable bottom end, produced a claimed 82 horsepower and had a maximum speed of 130mph. While the handling was not ideal, for many riders, the reliability and horsepower of the big Four made up for its shortcomings. This popular machine soon spawned variants, including the 750 and 650 versions built for countries where the tax structure made owning a 900 expensive, and the LTD cruiser of 1976, the first bike with cruiser styling.

In 1977 the Z1 was bumped out to 1,015cc, probably to cope with emissions regulations that had decreased the horsepower of later versions of the Z1. The new KZ1000 had triple disc brakes and a 4-into-2 exhaust, but the styling was very much like the Z1 of five years earlier. That all changed with the Z1-R.

The Z1-R

The Z1-R, released in 1978, was eye-catching. It sported café-racer styling, including an angular tank, tailpiece and a bikini fairing, all painted metallic silver. Engine upgrades and an innovative 4-into-1 exhaust produced a claimed 90 horses at 8,000rpm. Two of Kawasaki’s American executives, Graham Kirk and Wayne Moulton, had come up with the design concept in 1974, and worked with Japanese executives H.P. Otsuki and T. Takahashi to flesh out the idea. The stylist who translated the idea into sketches was “Cowboy Chris” Kurishima. The first mock-up appeared in 1976, and advance publicity started in 1977.

At the time, Kawasaki was developing a new model range, which was far from ready, and needed time to finish the R&D work on the new bikes. The KZ1000, although saddled with the existing and outdated frame and engine, had enough horsepower and style to keep consumer interest while the bugs were worked out of the next generation bikes.

Café racers had been developed by urban English riders of the mid-Sixties, who customized their bikes to perform on twisty roads just outside of town. In the late Seventies, several manufacturers, newly interested in handling as well as horsepower, picked up on the café racer look to signal that their machines would perform on a curve. Ducati had always been interested in handling, (its 900SS was a beautiful Italian take on the café-racer concept) but Kawasaki’s Z1-R, like Harley-Davidson’s XLCR and BMW’s R90S, was a departure for the company.

The Z1-R featured several advances. Aside from the steel tank and front fender, all the bodywork was either fiberglass or injection-molded plastic. The quarter fairing was the first on a Japanese motorcycle. The 7-inch quartz halogen headlight was not a motorcycle first, but was state of the art for the time, and one of the first on a motorcycle built in Japan. The black coating on the engine was not painted, but laid down by an electrical process that provided a durable finish. Triple disc brakes featuring drilled rotors and a cable operated remote master cylinder on the front brake were also a Japanese bike first. The self-canceling turn signals were a first for Kawasaki.

On the road

Contemporary magazines liked the Z1-R. They liked the styling and the silver paint, but what really got the attention of period testers was the increased horsepower, due to the larger carburetors and the improved exhaust system. Cycle magazine managed to wring an 11.95-second quarter-mile time out of their test bike and put the feat on the front cover of the magazine. Cycle World wondered what the maximum speed would be — their test track wasn’t long enough. The factory claimed a top speed of 130mph.

The rest of what period testers liked about the Z1-R was what they had always liked about Kawasaki Z’s: the powerful but reliable engine, with loads of midrange power, the five well-spaced gears and the quiet exhaust. They tiptoed around the okay but not perfect handling, having to point out that although the swingarm had been treated to needle roller bearings and the front downtubes had been reinforced with a heavier gusset over the steering head, what was really needed was the new frame design that was still a year or two away. Cycle also pointed out that the suspension was “substantially oversprung and slightly underdamped,” and the fork springs were too harsh, producing a ride that could be unpleasant over bumps. Cycle World said the ZI-R “doesn’t like sudden changes in direction.”

Both magazines agreed that, on smooth pavement, the seat was surprisingly comfortable, the riding position was good, and the fairing worked well as a wind deflector, in addition to being a styling plus. Trace testifies to the abilities of the Z1-R as a mileage eater — his two coast-to-coast jaunts were accomplished comfortably and in good time.

Most Kawasaki owners of the time liked their bikes. Cycle World did a Kawasaki owner survey in 1980, and it included the owners of 16 Z1-R’s. Riders said the best features of their Kawasakis was their reliability, speed and power, and the worst feature was their handling. Despite awareness of the faults, 88 percent of owners said they would buy another Kawasaki. The shortcomings of 1970s Kawasakis in the handling department gave a marketing opportunity to aftermarket frame manufacturers, such as Kosman and Rickman, and builders of frame stiffening kits.

Some 17,000 of the D1 version of the Z1-R were built for the 1978 model year. The D2 (1979) version was not imported to the U.S. In its place, Kawasaki introduced the KZ1000 MkII, with the improved frame, forks, and front and rear suspension that Kawasaki’s engineers had been working on for several years. For 1980, the ZI-R reappeared as the D3, minus the silver paint, and with the updated frame, suspension and steering geometry from the 1979 Mk II. A 19-inch front tire helped with roadholding. By this time, Kawasaki had finished the R&D on the next generation of Superbikes, and the Z1-R again faded from the lineup in 1981. Only 3,300 of the D3’s were produced.

Z1-R No. 3

In the meantime, Trace bought a faster drag racer and gave his Z1-R dragger to his son, who was following in Pop’s racing. Several years ago, Trace got the bike back. “I realized it was more fun to run. It’s very consistent, and I can make my pass and ride back to the pits. The more powerful bike had to be towed back. Also, it looks old school and gets noticed. People give me compliments.”

The show bike (Trace’s third Z1-R) was found about a year and a half ago laying on its side in a barn. Mice had eaten the seat, and were using the airbox and exhaust as a hotel. The person who found it put it on Craigslist. Trace was idly poking through the website one day — and there it was. He made a deal and brought it back to his shop. Trace had stockpiled Z1-R parts over the years, and this project made a good dent in the parts bin. As he explains: “I had to replace the cylinders — the originals were corroded. Luckily, I had another set of cylinders. The pistons were great. All I had to do was replace the rings and hone the cylinders. The valves were good and the lower end was good. The wiring harness had been hacked up, and I replaced it with the wiring harness from my race bike.”

“There was a little rust in the pipes, and I had to have them rechromed.” Rechroming was a multi-step process, involving cutting the exhaust into pieces and rewelding them. “I rewelded using the same process as the Kawasaki factory,” says Trace, who likes to keep things original. “The brakes were bad, and I had to rebuild the master cylinder and calipers, and hone the master cylinder. Finding a rebuild kit for the front brake master cylinder (a ZI-R-only item) took months. I finally found one in England.”

Trace has learned to work efficiently. He starts a project by disassembling the motorcycle, and making lists of items that need to be replaced, items that need to be rebuilt, items that need to be repainted and items that need to be rechromed. Then, he gets the parts that need to be sent out to the painter and the chrome shop together, sends them out, and starts looking for replacement parts while he rebuilds and refinishes items that will be refurbished in-house. As a result of Trace’s organized approach, once all parts were on hand and ready to be reassembled, it took him three weeks to put the whole bike together. The ZI-R was finished the end of April 2019, and taken to The Quail Motorcycle Gathering in Carmel, California, two weeks later. It took home the second place trophy in the Japanese class.

1970s big-bore Kawasakis are known to be reliable, and they continue to be reliable as long as the oil is changed on a regular basis. “It’s a maintenance-free bike,” Trace says. “I occasionally flush the hydraulic brakes. I change the oil and check the valves once a year. The oil should be changed every 2,000-3,000 miles. I like to run the valves a little looser than factory recommendations, which is the general consensus of mechanics. The factory manual says 2-4 thousandths, and I set the valves at 4-6 thousandths.”

“With the little fairing, I don’t get beat up as much on the long hauls. The stock bike is not the best handler, which is why everyone bought those frame stiffening kits. It’s great for big sweepers and long distances. The cable operated master cylinder works well, but has a slightly spongy feeling.”

“When I ride my bike on the street, I turn heads. I know this bike inside and out. I have always liked the styling. I have other bikes, but I don’t have the attachment to them like I do to my Z1-Rs.” MC