History of the KZ650

In North America it was known as the KZ650. To the rest of the world, it was called the Z650. It gained the name of ‘Son of Z1’ because both the Z1/900 and the 650 were designed by Gyoici “Ben” Inamura in the mid seventy’s. The idea came from the fact the people wanted a bike that was not too bulky and heavy, but with the character of a sport bike. The idea was to have the agility and nimbleness of the smaller 500, but the responsiveness of the 750. It also needed to be comfortable enough for the average person to ride long distances. Thus, the birth of Kawasaki’s best all around bike thus far.

The premier release of the 650 took place in the United Kingdom in 1976 where the world press was finally able to see and test the bike for the first time. With it’s 4 into 2 exhaust system and huge cylinder head, you thought you were riding a 750 and not a 650. The 64bhp was claimed with a dry weight of only 465 lbs, making a top speed of nearly 120mph possible. For once, all the available power could be used in relative safety.

During its lifetime, the KZ650 gained a reputation as a good, reliable all around bike. It was built until 1983, and was followed by the liquid cooled GPZ600 of Kawasaki.

The KZ650 engine block itself looked like a smaller version of the block of the Z900, but it was a complete new design. Lots of things were re-designed to make the engine run smoother and make less mechanical noise. Plain bearings replaced the Z1 roller bearing supporting the crankshaft but, more significantly, a Hy-Vo chain was the main drive between the crankshaft and the transmission versus the direct gear drive of the Z1. These enhancements reduced manufacturing costs but also made it a quite comfortable bike too, even when driving long distances. A bike to have lots of fun with!! Even after more than 30 years!!

The difference between the Z650 and the 750’s that came before it was that it handled and stopped. The reputation of big Kawasaki’s as being evil handling monsters was finally laid to rest with the 650. The Z650, however, easily out cornered almost everything in its class.

Changes to the Z650’s engine over its seven year stint were few. It gained a Hy-Vo cam chain (with inverted teeth for better sprocket grip and therefore quieter running) and an automatic chain tensioner from the 1980, and a leak-prone tachometer cable exit from the head was blanked off when the Z650F gained electronic tachometers. Other than that, Kawasaki left the lump unchanged.

Not only has the 650 and its spin-offs proved to be astonishingly reliable, their components can be mixed and matched almost at will. Plenty of people, for example, bore Z650s out to 750, or mount a 750 top end onto the 650 bottom end.

The Z650 has a purity of line and sense of proportion that very few Japanese bikes have ever achieved.