wr450 Exhaust Valve Failure

Anyone experienced an exhaust valve failure? I have a 2004 WR450, with approximately 2000 miles. I have kept up on all the maintenance, including monitoring valve clearances. Lost the valve cotter and the valve has dropped into the cylinder. Any ideas? I bought the WR specifically for the bullet proof top end (unlike the 450x), now I am troubled by this event.

Thanks

I think it's a pretty rare event. I have had four 4xx's with tens of thousands of miles combined. 0 problems. How do you lose a valve cotter? If you are referring to the retainer which is under the shim and cap it would seem pretty difficult to do if everything is assembled correctly.

I am assuming that it is the valve cotter....i have yet to disassemble the head/cam etc but I can see the top of the valve stem in the exhaust port of the head......I am really bothered by this as I like to go on long dual sport rides with buddies and a failure like this a few hundred miles out in the boonies would be a pain in the rear.

I don't know what caused this failure but it's not a normal occurance. I did 1600 miles in 8 days last summer DS with no issues. Longest day 275 miles about 90% dirt. Just make sure it's fixed right and ride. :banana:

I don't know what caused this failure but it's not a normal occurance. I did 1600 miles in 8 days last summer DS with no issues. Longest day 275 miles about 90% dirt. Just make sure it's fixed right and ride. :lol:

i agree...my 06 went 11k miles before i sold it...not one valve adjust...:banana:

fix it and move on you will be fine:ride:

Thanks all for the replies.....once I tear it down, I will fill you all in with the failure details.

i agree...my 06 went 11k miles before i sold it...not one valve adjust...:banana:

fix it and move on you will be fine:ride:

whoohoo!!

good to know i got a good year! my 06 is at 5k right now and have yet to shim the valves!

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