The Z2 was an almost identical motorcycle to the Z1 aside from its engine. A modified bore and stroke, smaller carburettors and a new crankshaft formed the basis of the 750cc inline-four that produced 69bhp and was capable of a respectable 12.5 second quarter mile pass. It was no Z1, but it could certainly hold its own against Honda’s main rival.
The last time we visited ‘Ruffo Black Customs’ in Argentina, workshop owner Sergio Ruffus had just wrapped up his KZ650 cafe racer. For his latest build, he looked to the Z2 platform reaffirming his love of mid-sized Kawasaki’s of the seventies. His Z2, which has been coined the ‘7Fifty’, is what he refers to as a “sportier cafe racer” that has hints of streetfighter and modern sportsbike integrated into its construction.
The first cab off the ranks for the Z2 rebuild was freeing up the flow of gases and increasing horsepower. For this Sergio installed a quartet of tapered oval filters, a 4-into-1 exhaust system wearing an Akrapovic muffler and the carburettors were tuned to suit.
For handling improvements, he looked for a modern donor that would compliment the Zeds geometry. The front end solution was found on a Kawasaki Versys. The Upside Down front end was custom fit to the neck of the Z2 frame and an ER6N wheel was installed complete with its brake setup. At the rear end, things got a little more complicated. Sergio wanted a stripped back, kicked up tail end similar to that of a modern sportsbike. To achieve this he cut away the original shock mounts and modified the frame to allow fitment of the ER6N swingarm and mono shock.
With the airbox gone the space it occupied was tasked with holding the bikes electrics and battery which are kept cool by a custom made set of side panels with integrated air scoops. To retain a classic aesthetic a KZ650 tank was modified to slip over the Zed’s backbone and a new seat was fabricated and covered in diamond stitched black leather. A new tail loop with flush mounted LED tail light and indicators closes off the bikes modified subframe.
Other styling modifications include Clip-on handlebars wearing bar end mirrors, an aftermarket speedo and headlight and alloy footpegs. Originally the Z2 was only made available in a rather unspirited brown/orange combo so Sergio had his friend Federico Teibo finish the build using a vibrant Kawasaki blue.
In the early 1970s, after being beaten to the line by Honda with the release of their CB750, Kawasaki halted the development of their own 750 four in favour of producing a larger capacity motorcycle that would put Honda back in their place. The bike they tasked with the job was the legendary Z1 which at the time was the most powerful 4 cylinder, 4 stroke ever made for consumer sale. Requiring a motorcycle befitted their own Japanese market Kawasaki completed the construction of the 750cc Z2, also known as the Z750 RS, and released it a few short months after the Z1. Thanks to the huge popularity of the Z1 the Z2 enjoyed similar success stealing more sales away from the CB750.