#1970 harley davidson golf cart parts series#

The fuel tank, fenders, and rear seat/fender combination were fiberglass, with a snap down seat cover over a foam cushion. The frame and the running gear were held over from the KRTT racer, with a Ceriani front fork and two Girling rear shocks. The engine was again re-designed for 1972 with an all-aluminum head and cylinder package with bigger bore and shorter stroke for the same 750cc displacement. These iron head XR-750s of 1970вЂ“71 were prone to overheating (humorously called 'waffle irons') as well as having insufficient power. It was too large to be legal, so a modified version was created using the same basic upper end parts (iron heads and cylinders) but with a drastically shorter stroke and shorter connecting rods to reduce the displacement to the 750В cc (46В cuВ in) legal limit. With limited time and money in 1969, Harley-Davidson's racing manager Dick O'Brien and his team used elements of existing designs to put together a new OHV racer, but rather than start from scratch they decided to modify their existing OHV racer: the Sportster-based 900В cc (55В cuВ in) XLR magneto-equipped race engine with a 3.0000В in (7.620В cm) bore and a 3.8125В in (9.684В cm) stroke. OHV engines began to dominate racing, in spite of Mert Lawwill's efforts to delay the inevitable on his flathead Harleys, and the KR bikes were a decade out of date and could no longer compete successfully. With the British marques gaining influence in the AMA, in 1969 new rules were established that there would be one maximum displacement for dirt track racing, 750В cc, with no regard for valve type, though the 500/750 OHV/sidevalve split was kept for the time being in road racing. The public was buying 650В cc (40В cuВ in) and larger displacement British bikes, and they would prove to be competitive, given the chance.

#1970 harley davidson golf cart parts series#

The flathead Harley-Davidson KR series had dominated Class C racing, but by the late 1960s BSA, Norton and Triumph had little market for 500В cc OHV motorcycles, and there was increasing pressure for a single displacement, without reference to valve configuration.

At least 200 homologated examples of a model had to be built and made available to the public. Over time, this displacement advantage kept the older flathead technology on the track and discouraged a broader field of competitors. 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 750В cc (46В cuВ in) displacement, while more modern overhead valve (OHV) engines could be a maximum of only 500В cc (31В cuВ in). Triple chain primary, 4-speed, chain final drive An XR-750 was included in the 1998 The Art of the Motorcycle exhibition, and one of Knievel's bikes is in the Smithsonian's National Museum of American History America on the Move exhibit. Knievel used the bike from December 1970 until his final jump in January 1977. The XR-750 is associated with the careers of racers Mark Brelsford, Cal Rayborn, and Jay Springsteen, and was the favorite motorcycle of stunt performer Evel Knievel. The XR-750 went on to win the most races in the history of American Motorcyclist Association (AMA) racing.

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 motorcycles to outperform the previously dominant Harley-Davidson KR race bike. 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. An XR-750, number 16, through the dust at Scioto Downs, Ohio