Up close: Kawasaki’s 250cc SR1

Despite Kawasaki’s denial that the bike ever existed, this 250cc S1R prototype was constructed in 1972 (together with a 350cc triple).

Officially, this bike doesn’t exist – and never did. Well, that’s pushing it a bit (here’s a large photoshoot about it after all) but for a while at least, Kawasaki wouldn’t admit to the SR1 being real. Up close, it’s flippin’ lovely.

CORRESPONDENCE WITH AN EX-FACTORY RIDER IN JAPAN AND FACTORY MECHANICS IN THE US CONFIRM THAT SINGLE EXAMPLES OF BOTH 250CC AND 350CC TRIPLES WERE DEVELOPED IN 1972. TESTED AT SUZUKA AND YATABE THEY PROVED TO BE UNCOMPETITIVE AGAINST THE TD1 AND TD3 YAMAHAS OF THE TIME. IT WAS DURING ONE OF THESE TESTS THAT THE 350CC S2R WAS CRASHED HEAVILY AND WRITTEN OFF. THE FACTORY THEN CHOSE TO FOCUS ON THE H2R PROJECT AND WORK ON THE SMALLER BIKES WAS SHELVED.

“GIVEN THE WORLD CHAMPIONSHIP REGULATIONS HAD BEEN CHANGED SO AS TO LIMIT THE 250CC CLASS TO A MAXIMUM OF TWO CYLINDERS FROM 1970, IT IS DIFFICULT TO UNDERSTAND THE COMPANY’S INTEREST IN A 250CC TRIPLE. PERHAPS IT WAS DESTINED FOR JAPANESE DOMESTIC COMPETITION HAD IT PROVED SUCCESSFUL?”

The generoussized four leading shoe front brake is a factory item, sourced from the H1R and A1RA.

Above:this motor was then shipped to tuner Mack Kambayaski in Southern California, to see if he could make a competitive bike from it. It was raced a few times, once at Virginia International Raceway, but did not prove successful. The rolling chassis was from Dick Hammer’s 1969 A1RA. Below: Apart from the unique dry clutch, other factory touches include raised cylinders, spigotted cylinder to head and the inlets welded up to take larger carburettors. A close-ratio six-speed gearbox is fitted.the pistons however, are from the standard road bike motor. Right: The carburettors are 30mm in size as opposed to the street bike’s 22mm units. A very distinctive tank and colour!

Above: A special cast alloy cover fits over the H1RA (the second, 1971, version of the 500cc triple racer) ignition stator and rotor. Below: The two outside cylinders are swapped from normal to allow the exhausts to run between the frame rails in a very compact fashion. The frame seen here actually a “low-boy” A1RA/F5R unit, restored to original.