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Memorable Motorcycle Kawasaki Z1

Friday, July 27, 2007
Kawasaki cut no corners in terms of the engine. The all roller bearing crankshaft was made up of nine individual components and was over-engineered even for racing.
American riders were treated to one of the greatest motorcycles ever produced when the four-cylinder Kawasaki Z1 hit showrooms in the early 70s.
It's time to correct one of the popular myths which is becoming ever more prevalent in the motorcycling world. Thus: "When Honda launched its 750 "4" in 1968, the biking world fell on its knees and worshipped the new arrival."

Those of us who were there at the time know this not to be the case. What the Honda did was extremely, subtly, clever. Just as the German blitzkrieg solved the problem of the supposedly impregnable French Maginot defensive line, simply by going round the back of it, so Honda avoided the problem of selling a heavy, fairly dull, conservatively styled, four-cylinder motorcycle to hard core bike enthusiasts by ignoring them.

If the leather-clad, oil-stained Grand Prix enthusiasts didn't want to buy the bike then the Idaho potato farmer, who learned everything he knew about motorcycles from his first and only experience with a Honda Dream, certainly did.

Honda produced a smooth, stone-axe reliable streetbike with electric start and a maintenance-free lifestyle. This was life with a Honda "4". Go to garage. Open door. Wheel Honda on to driveway. Insert key. Start. Ride. Park in garage.

Rider input was restricted to occasionally putting gas in the tank. This was the new market which Honda recognized: two-wheeled car drivers.

Once Kawasaki's marketing reseach determined a four-cylinder would sell, the Japanese marque went to work and produced a DOHC design that would prove to be both powerful and reliable.
By contrast, us hardcore motorcyclists thought that the Honda was a boring, old-fashioned (even at launch) lump which held no attraction. What we wanted was a BSA Rocket "3" with its spine-tingling exhaust note and sublime handling. Except that in reality we didn't. We knew that the BSA would self-destruct before the Honda needed its second tank of gas. Lusting after a Triple was the norm. Writing a check out for one wasn't.

Despite Paul Smart's legendary win at Imola, only a fully paid up member of the biking masochist's club would want to ride a 1972 Ducati Desmo. Appalling electrics, paint applied by a blind baboon with a migraine and hemorrhoid-inducing vibration meant Ducati's iconic V-twin was never going to be a mass market product.

What we wanted was a Honda "4" with biking sex appeal. We wanted a bike which was fast and reliable but we also wanted a motorcycle which induced lust. We wanted a bike which demanded to be stroked as the last thing before we went to sleep at night - a motorcycle which we had to touch before we left for work in the morning. We wanted a Kawasaki Z1.

In fact, the big Kwack was born twice. The first Kawasaki "4" was running and, almost, ready for launch in October 1968. This was good news and bad news for Kawasaki. The bad news was that Honda revealed its 750cc "4" at the Tokyo show of that year. The good news was that Kawasaki scrapped their conservatively conceived four-cylinder machine and declared all out war on their Japanese competitor.

The T103, as the bike was known internally in Kawasaki, was given top priority. The best of the Meguro engineers, the Japanese company taken over by Kawasaki, were drafted in along with the Kawasaki staff who had done so well with the two-stroke triples.

A lot of consumer research was done, primarily in America, to confirm that there was indeed a market for a high performance "4" and then, in the Spring of 1971, the first prototype was shipped to America for what has become a legendary test program.

In America, T103 became "Project New York Steak". Lead by Kawasaki America's senior test rider, Bryon Farnsworth, and assisted by Kawasaki's race team of Gary Nixon, Hurley Wilvert and Paul Smart, the new Kawasaki was subjected to repeated attempts to break it.
So what made the Kawasaki such a great motorcycle  First and foremost it was  and is  utterly  lust-inducingly gorgeous.
The secret to the Kawasaki's success went beyond it's four-cylinder motor - this Kwakker was a looker with all the right lines.

One item on the test program was undertaken at the Talladega speed bowl. The idea was to run the big Kwack flat out for the capacity of the gas tank: quite literally nailed hard against the stop. Test riders reported weaving but, even when running at a genuine 130-mph plus, the bike was unbreakable.

On normal roads, the T103 was run 8,000 miles from LA to Daytona and back, this time thinly disguised as a Honda "4". Drive chains lasted only 3,000 miles and tires only twice this distance but the all new engine was bomb-proof.

Despite the encouragement from their test riders, Kawasaki were still nervous about the potential success of their new flagship and so production was set at a modest 1500 units a month. By 1975, 5,000 Z1s were pouring from Kawasaki's production line.

So what made the Kawasaki such a great motorcycle? First and foremost it was, and is, utterly, lust-inducingly gorgeous. The fit and finish was exemplary and the styling breathtaking. Instead of the big, fat, middle-aged car driver's gas tank and saddle of the Honda, the Kwack looked light and slim. Incidentally, it wasn't weighing in at a fully adult 540lbs.

The kicked up rear seat fairing, slim saddle and aggressive exhaust pipes looked like a motorcyclist's bike - a machine that you rushed home from work and just rode and rode and rode simply because it was king of all it surveyed. On a Z1 you were top of the gas-powered tree - on two or four wheels.

Although a fun ride, the Z1's handling left much to be desired and even with dual front discs, the stopping power wasn't able to match the motor, which could get the Kwakker up to 140 mph.

But the Kawasaki was far more than just a pretty face. The engineering was exemplary and clever too. Everything except really major maintenance could be done with the engine in the frame. The motor might have been DOHC, normally the realm of GP racers of the day, but it was simple and totally unbreakable in even hard use.

Kawasaki cut no corners in terms of the engine. The all roller bearing crankshaft was made up of nine individual components and was over-engineered even for racing. The eight-plate clutch was huge and unbreakable and the pinions in the five-speed gearbox massive. Little wonder then, that these engines are still raced today.

The handling was less good. In fact, it wasn't very good at all! The first major problem was the Dunlop "Gold Seal" tires. They were absolute rubbish in the dry of California. In soggy England, they became lethal.

The rear dampers were a joke, the front forks very marginal and, even with a twin-disc front end, riding the Kwack at near its 140 mph potential top speed - and yes, they would run up to this sort of speed day in and day out - was a life-threatening exercise.

Another problem was a high-speed front end weave which then amplified to become a full blown tank-slapper simply because the chassis - a fairly direct lift from the ill handling two-stroke triples - was not up to the job of managing the big 80-hp engine. The steering damper on a Z1 was as essential as the bike's wheels or engine.

Riding a Z1 today is still a wonderful experience - right at the top of the classic bike tree. With modern tires and decent rear dampers, the bike's handling is transformed and the big Kwack will waft effortlessly up to 80 mph on a whiff of throttle and cruise there all day long.
The Kawasaki was far more than just a pretty face. The engineering was exemplary and clever too.
Although now belonging to the classic bike world, the Kawasaki Z1 holds its own and is still a joy to ride.

The Z1 is a practical bike too, being just as reliable as ever and with a fine supply of parts - many provided by Kawasaki's original suppliers. The only downside is the price. The Z1's virtues are widely recognized and therefore expect to pay an eye-watering $20,000 for a really stunning Z1, Z1A or Z1B.

For more information contact z-power.co.uk who are both extremely helpful and incredibly knowledgeable.

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woody35   June 19, 2013 12:19 AM
I have a ZIB exactly the same as the one in your article. I live in Hervey Bay Australia and wherever I go it attracts a crowd. It is restored to new condition and you cant beat that sound.It looks so modern even though it is 38 years old.
TerryC   April 16, 2013 06:14 AM
Loved the article,agree with every word on the Z1,mis the one I had.but here in australia so few Z1 left.Knew a guy who was one of the first to turbocharge a Z1,he claimed at high speed the front end was so light it was frightening to try and handle.GREAT BIKE!
VanGo   October 12, 2011 10:59 PM
Greetings! Had to comment, I bought a '74 z1 in 1974, brand new. Had to put up a $200. deposit to get my name on waitting list. Cost new $2,400. FANTASTIC BIKE!! Everything you hear and more! Per owners mannual, 5th gear for 85 mph+. I would get looks and questions from everyone, even police. I would love to have one again!
Roger Decker -Just Purchased a 1975 Z1 900.  January 13, 2011 06:23 AM
I have always been intrigued with the Z1s. I have owned many Kawasaki motorcycles from the 100 Trail Boss in my early years through the awesome KX450F, which I crashed racing motocross. After crashing the 450 and breaking my leg badly, I can't race motocross any more. I've deceided to move on to street bikes now, vintage iron in particular. I can't think of a better bike to start with then a '75 Z1.

I've purchased a '75 Z1 with just under 13,000 miles on it. The owner is the original owner, unfortunately he wrecked the bike several years ago and smoked the headlight & tach/speedo/meter unit and the rear fender. The sources I come across so far for these parts are way to expensive. Does anyone know of a source that sells these parts for a reasonable price?

I'm picking up this bike this weekend. I'm so excited to get started on this project I can barely stand it. Can't wait to light up the engine and take it for a ride.
Roman -The Duke  June 24, 2010 07:37 PM
I just bought a 75 Kawasaki KZ900 Z1B, took it to the shop and the mechanics mouth dropped, cherry condition. He fixed the carbs (been sitting for 4 years)he called me when he finished it. I haven't ridden in a few years, but I can tell you for a 30 year old bike it ran beautiful. I've never owned anything but Kawasakis, they are bullet proof.!
Bob Lincoln -Z1 vs. CB750  June 10, 2010 06:16 PM
In the late 70's and into the mid 80's I was a motorcycle mechanic; Honda, Kawasaki, & Yamaha certified (now I'm a design engineer). In my experience, the CB750 Honda was a fat, slow, ugly lump. It was a pain to work on (you had to pull the engine to replace the cam cover gasket let alone the head gasket which always leaked). A good running Trident, Norton Commando, or BSA Rocket 3 would blow the Honda's doors right off. When Kawasaki introduced the Z1, it was the new benchmark. The bar had been raised by a lot. It was so much more machine than anything else available. Kawasaki showed the world, and especially Honda, how a motorcycle was to be designed, engineered, and built. I am so sick of hearing that the CB750 was the first Superbike. 1: The CB750 was not a Superbike. 2: The FIRST Superbike was the Vincent Black Shadow. 3: The First Japanese Superbike was most definately the 1973 Z1 Kawasaki. Look at the racing history of the Z1 and the Z1 based bikes (KZ900 & KZ1000). What kind of racing history does that porker CB have? Yes there were a couple of CB750 based racers, but it was nothing compared to how many Z1's and KZ's that were raced and won races. I owned a KZ1000Mk2 in the early 80's and I was stupid for selling it. I miss that bike tremendously. I am not a brand snob, I've owned Japanese, American, British, and Italian bikes. I've ridden and worked on almost everything out there, and I can tell you that every motorcycle company makes something good and something bad. In 73, 74, 75, 76, 77, 78, 79, & 80 Kawasaki made something GREAT. (the J-Models were problematic). Currently I own an 02 Buell M2, a 95 Buell S2, an 81 Yamaha XV920R cafe racer, a 77 Yamaha XS650, an 83 Seca 900, a 67 Triumph Bonneville, a 46 Norton Model 18, an 86 Yamaha SRX 600, and several other project bikes. This weekend I am trading my beautifully running Seca 900 for two non running Z1's. What a deal! I am so excited, I cannot wait to begin restoration work on these bikes. By the way, great article. Thanks.
Drew -76 KZ 900  February 22, 2010 09:17 PM
This was my third motorcycle and by far the fastest, most reliable and best looking bike I ever had. Drove it to California from Texas one summer. Drag raced it with 50,000 miles and beat a GPZ 750 all three times one night! What an awesome bike! Like others out there, I wish I still had it. May try to get my hands on another before I grow too old.
john wells-astoria oregon -new old bike  January 3, 2010 10:43 PM
that would be so cool if kawisaki would do like they are doing with the muscle cars and produce a replica of the Z1-900 wow!but make it handle just a tad bit better,lol.
john wells -talk me out of it  January 3, 2010 10:36 PM
i have a fine 73 Z-1 i have been restoring for many years and i am about 800 bucks short of finnish.problem is hard times and thinking about selling.somebody please stop me!!
i had a 77 kz 1000 for a long time,but got cooned by a hit run driver in california,sick everytime i think about it.i need to get this bike on the road,when you can get on your bike and ride you can make anything happen!
K. Beckman -Ducati slanging.  November 28, 2009 03:10 PM
Perhaps it was a typo but the Ducati V-twins, particularly the 750s, vibrated hardly at all. Perhaps Mr. Melling was referring to the ride quality, which was a bit firm. If your 750 Ducati is vibrating at anything besides top whack, you probably need engine work. I have a December 1972 Z-1 here and it still impresses. If you weren't around in '73, you've got no inkling of what an impact the Z-1 had. It was as if a race of advanced aliens had taken it upon themselves to make a fast motorcycle for Earthlings. In fact, there were few, if any, stock bikes that you could not beat even if you had the girlfiend on the pilllion.
todd -Z1/Z1A/Z1B/Z2:1972-75 engine numbers  October 15, 2009 03:28 AM
Where can info be found on engine numbers and year they are used in?
Colleen Haugland -Kawasaki 900  September 17, 2009 09:43 AM
I have an original 1974 Kawasaki 900. It belonged to my late husband. He was the first and only owner. I need to sell the bike. Where does one go to peddle a bike like this?
todd Z1E 900 engine -stated wrong engine numbers  April 19, 2009 06:50 AM
engine numbers are Z1E 00390 NOT 003900
todd -73 Z1900 engine complete lower block  April 19, 2009 06:48 AM
saves a wrecked 73 Z1 from scrap yard. fromt damage, tank damage, twisted rear frame. Kept engine in garage the past 25yrs. sold jug and head off engine as well as carbs. am selling some of my collection. this block engine numbers are Z1E 003900, was told this is the earily build. what would be an accurate asking price?? tm53chev@yahoo.com
Bill -1975 Z-1 900 (Z1B)  April 15, 2009 09:53 AM
I just wanted to say that I agree with the previous posts. I am 26 and own two 75 Z-1's. Both are stock with the exception of exhausts and one has K&N's with some carb work. I was given both by my father, who owned the bike with K&N's since it came from the dealership. The second came from his friend who also owned his from the dealership. I have a new sport bike as well, but still get more satisfaction while riding either of the 900's.
leanier carter -kawasaki z1 900  March 31, 2009 05:04 PM
the best motorcycle that I ever owned, bought a kz900 A1 in the summer of 1976 and I wish now that I never had sold it to buy my first house, why won't kawasaki build a new z1 with that classic 70's style let kawasaki know their is a market out here for classic bikes of the 70's.
leanier carter -bought a 1976 model  November 19, 2008 11:38 AM
This is the only motorcycle brand that I have ever owned, a 1976 kz900 a 1979 kz1000 mk11, a 1981 kz1100 full touring model, I am 58 years old and do not like modern day street bikes with low bars engine encased, give us baby boon generation the bike we all grew up with, with classic z1 style in a modern interpatation not all this weird styling that we see today, let kawasaki know how a lot of us old guys feel theirs a market out their, a lot of guys like the style of the bikes of the 70's.