Memorable Motorcycle Kawasaki Z1

July 27, 2007
Frank Melling
Frank Melling
Contributing Editor| Articles|RSS

Our Memorable Motorcycles expert, Frank Melling also is the organizer of the British vintage motorcycle extravaganza known as Thundersprint. Melling began riding five decades ago and remains as much in love with motorcycles as when he drove his first bike into a cow shed wall aged ten. In the last 50 years, Melling has competed in every form of motorcycle sport and now declares himself to be too old to grow up and be sensible.

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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