The Kawasaki Z1: Evolution of the 'Z' family
Exactly 40 years ago, in September 1972, Kawasaki played its muscular hand and stunned the world with the launch of its four-cylinder Z1 motorcycle. For long known as the maker of some of the craziest and ultra-powerful two-stroke triples (in 500cc and 750cc displacements), Kawasaki had been doing their research which clearly indicated that the reign of the two-strokes was coming to an end and quickly at that.
Legislation in the US, the company’s biggest market was overwhelmingly stacked against the two-stroke so its engineers had got down to developing a motorcycle of 750cc capacity with enough tech to blow every ones’ socks off, including Honda’s!
Unfortunately for Kawasaki, old man Soichiro Honda was also contemplating on similar lines and was ahead by a couple of years when in 1969 the Big H unleashed the CB750 four-cylinder sohc motorcycle which was the first to offer so much tech in a road-going machine. This motorcycle sounded the death knell of the British motorcycle industry and it immediately catapulted Honda into the top shelf of performance motorcycling.
Kawasaki’s project team for their own four-cylinder machine revised its targets for their own motorcycle and they knew that it had to be bigger, stronger and more powerful than anything on the market then. The project code-named ‘New York Steak’ came up with the Z1 in 1972 and immediately it rocketed to the top of the heap on so many fronts. Unlike the Honda CB750, which featured a single overhead camshaft, the Kawasaki Z1 had Grand Prix lineage with double overhead camshafts operating four valves per cylinder.
If that was not all, the all-square cylinder dimensions of 66mm x 66mm meant that the bike displaced 903cc, put out a genuine 82bhp and rocketed to a 210km/h top speed, the first time a series production machine had cracked the proverbial double ton!
It immediately caught the fancy of so many tuners and racers and the bike did fantastically well all over the world. Key to this was the fact that the design engineers had endowed the Z1’s engine with a very robust bottom end, a detail that was to stand Kawasaki in good stead using just minor alterations to keep it at the head of the pack. Nothing illustrates this better than the 1982 GPz1100 having the same bottom end, an extra 200cc but now packing in 30 per cent more power!