Rotary-valve Racer
With Phil Aynsley
Kawasaki began its international road racing campaign a little later than the other manufacturers, not until 1966 in fact. Kawasaki 50, 125 and 250cc race bikes were fast but fragile, and technically behind the Suzuki and Yamaha V-4s and Honda 125/5.
NB: The images featured in this piece do not represent these early 50, 125 and 250cc machines but instead showcase the later F9-R. Which we get to later…
Indeed they had no victories at all early on, and despite designing their own 125cc water-cooled V4, they then quit GP racing at the end of that same year, 1966. However they did support Dave Simmonds with one of their 125 twins and some spare parts. The Englishman worked on the bikes himself and finished seventh in 1967 and 14th in 1968.
Things changed for the 1969 season with the FIM imposing cylinder limits for the various classes – which resulted in Honda, Suzuki and Yamaha all officially withdrawing from the GPs, although they did continue to support various riders at lower levels.
Simmonds then proceeded to win eight of the 11 rounds (missing the first round and placing second in the two others), giving Kawasaki its first world title (on a three-year-old bike)!
This somewhat ‘removed’ factory support is also seen with the F9-R pictured here. Kawasaki USA had decided to take advantage of the AMA’s revision of the rules for the Lightweight class for the 1970 season (those changes had been made to provide some competition for the dominant Yamaha TD2 250).
The 346cc rotary-valve motor from the F5 Bighorn trail bike was slotted into a slightly modified A1-RA frame to provide the basis for Kawasaki’s challenge. A close-ratio racing gearbox was fitted, together with a revised primary gear ratio, modified porting and disc valve, a Mikuni 35mm carburettor and an expansion chamber exhaust. H1-R wheels and brakes were used.
The F5 Big Horn’s motor had suffered from reliability problems however, so by 1972 it had been renamed the F9. When the road racing version was debuted later that year it was known as the F9-R. Output was 45hp.
Although the F9-R never won a race they did score many podium places, including a second with Yvon DuHamel behind Kenny Roberts at Charlotte in 1973. This particular example was campaigned by Art Baumann.
Source: MCNews.com.au