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    Harley-Davidson XR-750 - Wikipedia

    • The Harley-Davidson XR-750 is a racing motorcycle made by Harley-Davidson since 1970, primarily for dirt track racing, but also for road racing in the XRTT variant. The XR-750 was designed in response to a 1969 change in AMA Grand National Championship rules that leveled the playing field for makes other than Harley-Davidson, allowing Japanese and British … See more

    Rule changes obsolete KR racers

    The AMA Grand National Championship Class C rules, introduced in 1933 and revised in 1954, had an equivalency formula limiting flathead, or sidevalve, engines to 750 cc (46 cu in) displacement, while more … See more