Engine: Air-cooled V-twin 4-stroke
Ignition: Fairbanks-Morse magneto
Power rating: 46bhp @ 6,500rpm
Bore x Stroke: 2-3/4in x 3-13-16in
Fuel System: Single Tilloston carburetor
Suspension: Telescopic front forks, rigid rear
Top speed: 130mph
The flathead KR models were the backbone of American dirt track racing from 1952 thru 1969. Riders and tuners tried every trick in the book to improve performance, so no two machines were alike. With the power output approaching 50bhp, these sidevalvers were comparable in overall performance to the British 500cc overhead valve vertical twins. The uneven power pulses from the 45 degree design often gave them an advantage on a slippery race track to get traction.