I apologize up front, as I don't know a lot about 4-stroke bikes.
A buddy was riding my '03 WR450 yesterday and we came to a stop (after a stream crossing) and someone else noticed oil spitting out one of the half moon rubber nubs on the valve cover gasket. The rubber nub had torn away from the gasket itself and was sitting at a 45 degree angle. It is the side closer to the radiator, which I think is the exhaust camshaft cover.
We were able to press it back in and ride back to base. Upon closer inspection, we see that a vent hose (which runs outside of the skid plate) had been crushed/pinched closed (probably at a log crossing). I think it's labeled as the "Cylinder Head Breather Hose" in my manual.
Not jumping to conclusions, but I think that the pinching of this breather hose caused so much back pressure that the gasket blew out (I'm guessing that's design intent).
Anyone else ever experience this?
My plan is to:
- Flush the oil a few times - we don't know how long that nub was off and some of the water crossings were deep & messsy
- Remove the cylinder head, replace the gasket
- Check the Valve clearances (something new to me as well)
- Un-pinch the breather tube and re-route it inside of the skid plate
Should I have other causes for concerns?
Edited by ack1961, February 19, 2012 - 04:12 PM.