Hello all, new to the page and ATVs in general. Just picked up a 2003 Trx450es for cheap. It did not run but was in otherwise great shape. I pulled the head after it wouldn't turn over with the recoil starter. As I suspected, the piston was being blocked by what seems to be a broken valve seat. Ordering a new head and top end kit already, but is this something common on these? Is there something that was neglected to cause this? There was plenty of clean oil in the motor, no clear signs of abuse. Is there anything in particular that I should be aware of for these machines? From what I've read they seem to be pretty rugged. Thanks for any insight!