On the press launch for the 2009 Harley-Davidson XR1200 street-tracker, we were only a stone's throw from the Del Mar racetrack just north of San Diego, where 10 years ago I'd seen Scott Parker glide and slide around that loamy dirt-track on his XR-750 in a way that seemed to defy physics. His insistent artfulness to lead—and win—at the mile that day had also defied an upstart 18-year-old racer named... Nicky Hayden. As I cruised the pits back then, I ran into Willie G. Davidson himself. "To me, this is the best racing in the world. A dirt mile...there's nothing more exciting," he said. I had to agree, and it was talented riders like Parker and the rest who made that show.