Got a little over 2k miles on it. Did a 75 mile ride in the mountains. Then did 2 runs up to 140mph on my friends airstrip. As I downshifted to first it sounded funny. Pulled in the clutch and it quit running. Waited 10 minutes then barely fired up, would not idle, sounded rough as ****. Smoothed out after a min or two. Any idea what happened?