My son went riding today. Came back, and told me that the bike ran great until it just died (locked up). He said it was really hard to get the kick started to move but was finally able to get it to kick over and eventually start. He said it ran perfect? for 10mins idle and then he rode it over some whoops and the same thing happened. I went out to the shed (its dark now). It feels different kicking it over now, somehow out of time? It almost seems I can't get a full kick out of it without compression building at the bottom of the kick? Sounds like timing skipped? Is that possible on this bike? If not what could it be? How much to fix? Or is it simple? Sure does not sound good from what he told me and what I have felt out in the dark.