Living on the edge of Z.

After Soichiro Honda and the boys effectively laid down the superbike gauntlet with the Honda CB750, what choice did Kawasaki have but to issue an appropriate response? That’s exactly how the 1973 Kawasaki Z1 came about, and the 903cc air-cooled inline-four cylinder came along, packing twin cams into the bargain. All that, and good handling, too? 

“The Z1 handles as good as a Norton. I've been arguing about the Z1's handling with Norton people for years. [It] also handles much better than a 750 Honda of the same period,” lifelong bike lover’s bike lover Troyce Walls once told Motorcycle Classics. He knew those were fighting words, and he didn’t care a single bit. He believed them, and he’d ridden enough different bikes of the era to feel like he’d earned the right to have that opinion. 

Thanks in part to the Japanese motorcycle industry’s collective purchasing of newer manufacturing equipment during the 1960s and ‘70s, Japan’s Big Four were all able to meet increasingly rigorous mechanical specifications. Good handling was still a way off in those early years, but building state-of-the-art engines was suddenly well within reach. While the H1 had put Kawasaki on the map, and the company was betting on the Z1 to keep riders coming back for more. 

After the CB750 came out, Kawasaki had a bad case of ‘anything you can do, I can do better,’ and that’s in large part how the Z1 was born. Riders loved it. Code-named “New York Steak,” the bike was Japan’s largest and most powerful motorcycle ever built at its 1973 introduction. By 1975, European Z900 models gained dual front brake discs, while America still had to make do with a single disc setup. When 1976 rolled around, the rear of the new Z1000 caught up to the front, switching from a drum to a disc. (Incidentally, it’s stories like this that make me shake my head at how long drum brakes hung around on bikes, but I digress.) 

By 1979, Kawasaki still insisted on pushing technology forward, so the KZ1000H had fuel injection. After Eddie Lawson won the AMA Superbike title, Kawasaki put out a special KZ1000R for 1981. Then came the GPz1100, after which Kawasaki put its air-cooled Z series development on ice. It was less than ten years, but they did so much in such a short period of time. 

Sources: Motorcycle ClassicsMotorcyclistMotorcycle Classics