ack in 1969 the H1 (aka Mach III) certainly was big news. Not the biggest news because it arrived at just the same time as Honda’s CB750 and without a doubt a 750-4 trumped a 500-3, at least in terms of magazine headlines. However, there was no denying that a 60hp motor in a 174kg chassis was a potent brew – offering a better power-to-weight ratio than the Honda. In fact it blew the Honda off the road – or at least the drag strip, being good for a sub 13-second quarter mile, better than the CB750 by around half a second, while matching the top end of around 115-120mph. If you could keep it out of the hedges – not an easy task – it was a giant slayer. Kawasaki – who’d only stepped into motorcycle production seriously in 1959 (when they established their works at Akashi, then acquired rival Meguro) – came to the H1 via the A1 and A7 (that’s the 250cc Samurai and 350cc Avenger) twin-cylinder roadsters. These two had similarly been the proverbial bluetouch paper, but unlike the triple were disc-valve motors – as was being used on Kawasaki’s twincylinder then V4 grand prix 125cc road racers. With all the Japanese manufacturers stepping up the capacity categories in the late 1960s, the H1 was effectively Kawasaki’s first ‘big bike’, or high performance big bike at least, the earlier W1 650cc twin – based on BSA’S 650cc A7 – being a little, well, flaccid. But if the W1 was leisurely, the H1 was simply manic. Kawasaki, like Suzuki, had considered upsizing their twins to 500cc – and if that had been the case they would have kept the disc-valve induction, but their project engineer, Yukio Otsuki, also investigated the triple option – and liked what he saw. With a 120º crank the triple was better balanced than a twin and with three pistons the engine was pumping less torque through each of the cylinders which meant a lighter clutch and transmission could be used. Of course the layout meant forgoing the disc-valve induction, but even with
Suzuki may have played it safe with its two-stroke range in the late 1960s. But not Kawasaki, the green team went for broke with a succession of fast and furious strokers. Their first triple, the H1, took the biscuit though. Properly mental, you could say.