Okay. My kid ran his 04 WR450 into a tree at an enduro this past weekend, smashed the radiator on the left side and cracked the top tank. We gambled and tried to get it back to the next reset/gas before the water ran out. We lost the gamble and the bike died 2 miles before the gas stop. It rolls over, so it didn't sieze. It seems to have good compression, but with the auto decomp I'm not sure I'm getting a good feel for it.And I haven't done a true comp test yet. It has spark and seems to have fuel too, so I ruled out any kind of overheat sensor that it might have. There is a plastic plug in the head that faces forward just above the header that is now leaking oil onto the header. I imagine it got hot enough to melt that enough to leak. What is that plug for? My guess is a blown head gasket or a cracked head. I'm looking for suggestions from the hardcore yamaha 4stroke mechanics what to look for. I am very familiar with 4st bike motors, but not the 450 yamaha.