I was riding on a highway climbing a hill at about 60 when the engine locked up and skidded till I pulled the clutch in. I managed to safely pull it over to the side of the road. There was smoke pouring out of the engine around the cam area. I quickly tried to turn the engine over,(not trying to start it). It was stuck. I pushed harder and it turned over about twice as hard. The third time it gave and turned over normally. I let it cool off for a good 5-10 minutes then started it up. It started just fine. Do you think my piston seized and I managed to free it? The smoke kind of worried me, because I could also see this being a possible oil pump failure, but without an oil light who knows? Anyway I managed to ride it home safely, the power felt the same, it didn't try to die or anything. It starts up fine again after a couple hours. Should I be worried and check anything or should I just assume the piston froze from overheating?