While some racers had already wrapped up championships for the year, others were still in a fierce battle to claim an AMA number-one plate after nine months of competition at AMA National Enduro's ...

The XR750 was Harley-Davidson's most successful motorcycle built for the race track. It has won 28 of the 37 AMA Grand National Championships from 1972 ... The Sportster S follows the XR750's flat ...