connecting rods

ive got a problem im 23 my brother is 15 we both have predator 500s, my step dad got my brothers predator 500 rebuilt about 2 or 3 weeks ago they put a 12.5 high compression piston in it and shaved the head .002 and did a 5 angle valve job on it he has ran 3-4 tanks of gas threw it and tonight...

OK im looking into buying a 03 polaris sportsman 600, the guy said 1 of the connecting rods was going bad (he has the engine down) and i was looking on the parts diagrams and it doesn't seem like you could pull it apart to replace it, what the hell!!! And there doesn't seem to be any replacement...