2003 yz450f has had a new cp piston and rings(13:1), cam chain and pasted the valves for a fresh seal. put it back together and ran it for about an hour then i took it in the beach races, it went the best it has ever done never had it pull that hard. i stripped it down and touched up the frame, greased n cleaned everything. the bike sat for 12 or more months then i pull it out of the shed and took it on a forest trail for the arvo. the bike went good till the end after it got warm it was a hard to start and kept stalling worse then ever before. then at the end of the trail the bike started not idling and breaking down having *** moments. i check the carb nothing abnormal and the plug new. no change. then i took it out to another trail with a mate and after about 10 mins putting around and not idling i decided to give it a fang the in third gear it lock the back wheel and came to a stop. i took it home and tore it down to find the piston intake and exhaust side have marks in them and the wrist pin has mark on it. is there anything i should check for inside? the valves are all good nothing touched but the bike was binding up tight on the kick started? plz help!