1977 Kawasaki KR250 GP
As raced by Gregg Hansford
Kawasaki’s Grand Prix efforts began in 1966 with a 125cc water-cooled, disc-valve 2-stroke twin – which won the 1969 title with Dave Simmonds aboard. The KR3 V-4 was also developed from 1967.
The company’s 250cc efforts started in 1967 with the much less exotic A-1R, based on their road bike (Kawasaki A1-R 250 rotary valve racer) and later, a smaller version of their 350cc Bighorn motor.
It wasn’t until 1975 that their first dedicated racing design appeared, the KR250.
This was a tandem disc-valve twin with contra-rotating 180º cranks. The first bikes also used a conventional rear suspension layout but with only a single rear shock mounted on the RH side of the swingarm.
Problems with fierce engine vibration saw a 1977 redesign with the motor changing to a 360º “Twingle” layout with both pistons rising and falling together. A centrally mounted mono-shock rear suspension was also employed from this time.
The KR250 (and its KR350 sibling) were extremely successful from 1978 until they were retired in 1982.
Kork Ballington won both the ’78 and ‘79 250 and 350 titles, with team mate Gregg Hansford second in the 250 class and third in the 350 both years.
Anton Mang won the 250 title in ’80, ’81 and ’82 as well as the 350 title in ’81.
The design’s light weight, good power, narrow profile and excellent ground clearance were all major contributing factors in its dominance.
For 1978 the output was 62 hp at 12,000 rpm with a weight of 104 kg – which gave a top speed of around 250 km/h.
The bike seen here is the one raced by Hansford in 1977-78.
