KAWASAKI KZ1000, KZ900, Z1
"Kawasaki were as much surprised - and annoyed - by Honda's unveiling of the CB750 as everyone else. Determined not to be outdone, the design team went back to the drawing board and came up with a 900cc machine in a bid to make a bigger and better machine than the CB. The design brief included the order that there were to be 'no defects.'
The Z1 was undoubtedly superior to the Honda in that it had more bhp and a higher top speed. But it wasn't without its flaws, particularly in the braking and handling department and it wasn't as innovative as the Honda had been when it was launched.
Kawasaki copied the single disc front brake but with 82bhp on tap at 8,500rpm and a top speed of 130mph, the brake simply wasn't up to the job of pulling the Z1 to a halt. The bike was also heavier than the Honda at 229.5 kilos (506lbs).
And the notorious flex in the frame set the precedent of Kawasaki engines being too strong for their frames right up until the late 1980s.
Nevertheless, the Z1 became the new superbike king, it's 903cc, DOHC four cylinder engine being good enough to take the bike to no less than 45 American and world speed and acceleration records at Daytona in March of 1973. There had simply never been a production motorcycle as powerful as this.
Like the Honda, the £1088 Z1 featured a five speed gearbox, electric starter, the disc brake and four similar chromed exhausts.
The Z1 itself endured a four year production run in its original form but derivatives of the basic design can still be traced in the 'Z' Kawasakis of today. The Z motors found their way into race chassis such as the classic P&M but also they grew into true superbikes such as the American market KZ1000R as used by pre-GP stars Eddie Lawson and Wayne Rainey and later the and GPz1100.
Ironically, Kawasaki helped to kill off the trend for making big bore, two stroke multis which they themselves were so good at. The world had gone four stroke crazy thanks to the CB and the Z1."-15 September 2001
by Stuart Barker
Unique Kawasaki 750 two-stroker or the first Z1?
This introduction to the "prototype" Kawasaki Z1 was originally published in The Motorcycle News in the UK.
"Introduced in 1971, Kawasaki's classic 903cc four-cylinder Z1 was originally planned as a 750cc bike with a launch set for 1970.But with Honda's surprise intro of the CB750 in 1968, the story goes, Kawasaki postponed the Z1's release, in the course upping the bike's displacement in response to Honda's 750cc four. What's been missing — until now — are actual photos of the aborted 750cc Z1. Enter Jeff Krause.
Jeff grew up a coporate kid of American Kawasaki; his dad was involved in starting and managing several of Kawasaki's divisions in the U.S. in the 1960s and 1970s. By pure coincidence, in 1989, Jeff's first job as an industrial designer brought him to a little design firm in Santa Barbara called Bartlett Design Associates, which had previously been called McFarlane Design. Soon after being hired, Jeff was given a 35mm slide of an appearance prototype (a mockup) that McFarlane had done for American Kawasaki in 1969. The image speaks a thousand words to any Z1/KZ fan, and is the only picture of the aborted Kawasaki 750cc superbike we've ever seen. This is not Kawasaki's Z2 750cc bike sold much later in Japan, but the 750cc Z1 that Kawasaki was working on releasing by 1970, as evidenced by the license plate (curiously, the chrome license holder has the Triumph logo on it).
Aside from the photo's rarity, of interest is the fact that this appearance prototype obviously influenced the styling of Kawasaki's two-stroke triples of the mid-Seventies. Jeff says, "I take the image as evidence that the styling of Kawasaki's whole street lineup through the 1970s was actually developed right here in the good-old USA, not Japan. And that the Z1 was always intended to be a DOHC, even in 1968 or 1969 when this photo was taken, presumably at the design studio in Santa Barbara." McFarlane specialized in "Human Factors" and vehicular design, and designed the styling of Universal Studios' first tram buses, among many other equally significant credits."
In 1968 Kawasaki was far along in developing a 750cc in-line four cylinder to take the motorcycle world by storm when word got out of Honda's CB 750 Four.
Realizing 750cc’s would no longer cut it, and trying to get a jump on everyone else again, Kawasaki started testing 903cc prototypes in 1971. Disguised as CB570s ironically, by 72 the Kawasaki Z1s were ready for production. The project, originally dubbed "New York Steak" by Kawasaki was intended to be named the Super 4, but at some point was changed simply to the Z1. And thus a legend was born.
Where the Honda 750 was fast, reliable and cheap, it was also accused of being somewhat boring because it did everything so well but nothing in spectacular fashion. The same couldn’t be said of the Kawasaki Z1. It was blindingly fast, looked like a beast and captured the imagination of testers and the public the world over. With a quarter-mile time of 12.5 seconds and about a 135 mile an hour top speed right out of the box, the Z1 was a classic in the making.
Handling issues were to dog the Kawasaki Z line all through its production but complaints were few when this classic first came on the scene. In fact, later versions largely resolved the high speed weaves. And though outright performance never really improved over its many iterations, the Kawasaki Z1, KZ900 and KZ1000 would henceforth be known collectively and simply as “THE KING”!
Many different versions of the KZ series were manufactured in its long run, including cruiser models like the LTDs, and super-sports such as the Kawasaki Z1R.
The "J" models saw great racing success in superbike and endurance series the world over with the J in particular getting special attention from Kawasaki engineers. This fearsome unit got the benefit of a very rare eight spark-plug head design used only in factory racers. Named the "S1", these cylinder heads are much sought after collectables among Kawasaki collectors.
Among deserving recipients of Kawasakis' largess were the legendary Eddie Lawson and Canadian multiple champion Lang Hindle, who now makes high-end exhaust systems for bikes of all kinds.
|KZ series model name
||year of production
|KZ 900 Z1
|KZ 900 Z1A/B
|KZ 900 A4
|KZ 900 LTD
|KZ 1000 A1
|KZ 1000 A2
|KZ 1000 Z1-Classic
|KZ 1000 Z1-R B1
|KZ 1000 Z1-R B2/B3
|KZ 1000 Z1-R TIC Turbo
|KZ 1000 MKII
|KZ 1000D Spectre
|KZ 1000R Edie Lawson Replica
|KZ 1000R Edie Lawson Replica
Such was Eddie Lawsons' success that in 1983 Kawasaki produced the Eddie Lawson Replica, a relatively faithful copy of Lawsons' championship-winning mount. And yes, it's an eight-plug head.
Some local Kawasaki history written by journalist and racer Steve Bond
"One of the more famous motorcycles to wear the coveted Canadian Superbike Number One plate is Lang Hindle’s Kawasaki KZ1000. Not many people know it but Lang actually had two identical Kawasakis that shared the burden of being Numero Uno. Both equipped with the legendary Eddie Lawson S-1 Factory racing engine.
Bar Hodgson, Chairman of the Canadian Motorcycle Heritage Museum, through a long involved process, tracked down and resurrected both of the Hindle Superbikes, making them a unique addition to the museum’s competition collection. One Kawasaki was virtually a time capsule in running order, but the second KZ finally breathed life again just last summer.
Bar made it a priority project to get the second motorcycle operating and committed all of the museum’s substantial resources into accomplishing this goal. ‘I had to chase a lot of the stuff down myself,’ says Hodgson. "McLea had taken the rear wheel off the Superbike and grafted it onto one of his CBXs. The motor was in storage with a damaged head and many of the special parts were in unlabeled boxes. I’ve got to give Bob a lot of credit though, if guys like him hadn’t kept this stuff, it wouldn’t be here today."
The Hindle bikes are not pristine restorations but retain the delightful patina of working motorcycles; thoroughbreds destined for the racetrack wars, not for lounging around a sterile showroom. Both bikes are outfitted with Morris mag wheels on the back and Dymags on the front. Lang explained, "The Morris rear handled the horsepower better and was much more crash resistant."
The second bike required a substantial amount of re & re before it was trackworthy. Supershow’s Competition Manager Ken Livingstone explains. "We tore the engine down and discovered that everything was in pretty good shape except the cam chain and cylinder head. We replaced the cam chain and threw in a new set of rings as well. I replaced a few seals and small parts in the bottom end and Steve Crover did a great job finalizing the repair of the damaged head for us.
Not bad for a guy who hasn’t raced in twenty years." Ken says the ultra rare factory S-1 motor is surprisingly stock. "It has the twin-plug, full race cylinder head, but it’s still only 998cc - not the 1015cc mill. When Peter rode the bike at Mosport, it even had the original 33mm Mikuni Smooth Bore carbs with 31mm restrictor sleeves as mandated by period Superbike rules. After the event we strapped it onto the Hindle Exhaust Systems dyno and got 104 rear wheel horsepower. We then mounted some identical, but un-restricted carbs and got another 5 hp. But there’s probably another six or eight available if when we fiddle with timing and jetting."
The only ‘modern’ part on this motorcycle is the exhaust. "Lang was very supportive and made a modern 4-into-1 stainless steel system with aluminum canister for it. He also duplicated the original tach bracket and fork tube ears to mount the number plate."
VRRA rules prohibit slick tires so Avon AM22 and AM23 vintage-racing rubber was fitted, the rear in a 150-section. "I was impressed with the tires," Derry says. "I had a few slides but they were predictable and very easily controlled."
Both Superbikes have close-ratio 5 speed boxes with a tall first gear requiring some clutch slipping to get going from a standstill. Peter notes, "This bike has a VERY tall first gear, which made it difficult to get off the line."
"At first I thought the suspension felt very soft," says Derry.
Especially for Mosport but then I figured that Lang knew what he was doing so I left it alone and rode it the way it was. They feel tippy until you ride them hard, and then the harder you ride them, the better they work."
Front brakes are Lockheed two piston calipers gripping cast iron discs made by Hindle himself. Lang said the slots cut in the disc were from trial and error. When the brakes got hot, one side of the disc would get hotter than the other and the discs would warp. After he machined the slots, it allowed the rotors to expand at their own rates and the warping stopped.
VRRA rules allow motorcycles up to 1982 in Period 3 and the scene was set for a ding-dong battle in the final. Derry was aboard the Museums S-1 Kawasaki 'Hindle' bike and Livingstone was riding the Museum’s ex 'Eric Buell' Yamaha TZ750, the same bike I rode to a win in the Master’s class.
Ken and Peter quickly checked out from the rest of the field and the two battled tooth and nail for the lead. ‘The TZ had quite a bit of motor on the KZ up the backstraight,’ Derry notes. ‘But I started concentrating on getting a good drive out of the hairpin as Ken was having trouble keeping the Yamaha’s front wheel on the ground coming out of turn 5b and then spinning up the rear wheel in turn 6, causing him to back off a little.
They were neck and neck coming out of turn ten on the last lap and Derry and Livingstone squirted through lappers to a dead heat. A review call by the VRRA Officials announced that Peter had won the race by inches.
Peter was thrilled. "I had one huge moment when I touched the sidestand lug down in the chute but it’s a tribute to the bike’s stability that it didn’t do anything drastic. (Note - the offending lug that had been welded on when the bike was streetable has since been removed) I hadn’t raced since 1983 and it felt pretty good. My lap timer showed my best lap as 1:36.57, which is a new unofficial Mosport vintage lap record."
It was a fairy tale finish for Peter and for the museum’s legendary race bikes and Hodgson adds, "To see Lang’s bike win another race after almost 20 years made the entire effort worthwhile."
Lang prepares his former Superbike for another test run." "The plan was for Lang Hindle to actually race this machine at the Vintage Road Racing Association (VRRA) festival at Mosport in August’, adds Hodgson. ‘But he was called away for an important meeting in the US at the last minute. Peter Derry, Supershow’s Vice President of Sales raced Kawasaki Superbikes in the early 1980s, so I thought it was appropriate that Peter ride the newest ‘Hindle’ restoration for his Vintage Racing debut."
Toronto resident Bob McLea, who held an Expert roadracing license himself in the 1970s, got the second bike after Hindle had turned it into the ‘ultimate’ street bike. I actually saw this motorcycle several years ago in McLea’s back yard, sandwiched between a pair of modified CBXs and had no idea of its pedigree.
This bike was driven all over southern Ontario for years by Bob McLea (minus the S1 head of course) and was the ultimate Kawasaki streetfighter in disguise.