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-   -   Is it true the Raptor's engine has a valve/seat durability problem?? (https://atvconnection.com/forums/yamaha/56015-true-raptors-engine-has-valve-seat-durability-problem.html)

scottd Jan 29, 2002 10:05 PM

I think it was Mickey Dunlap @ FST that said that any Raptor with over 10 hrs. on the engine would be experiencing valve problems...specifically "mushrooming" of the valve face. (supposedly due to weak stock valve springs?) Has anyone heard of this? Has anyone had ANY valve problems on their stock Raptor engines, or have any reason to believe that this rumor is true? I hope all this stuff is not the case....but would sure like some feedback on what you guys have seen or experienced. Thanks!!! P.S. IF there is a problem, what is the fix?

THEMOOSE Jan 29, 2002 10:34 PM

While I was at my dealership today (M&W Powersports Broken Arrow OK) getting A oil filter I asked them about any problems they had noticed with Raptors. They said the only work they have done were Valve ajd,adding pipes & rejetting ,crash damage & replacing bent axles (3). No trannys no starters no valve problems. This is only one dealer in one area so take it for what its worth but they have sold a lot of Raptors.

raptor720 Jan 30, 2002 12:02 AM

If Mickey has seen valve issues I suspect they are true. He does provide some good tech info from time to time.

I have seen some valve sealing problems in addition to valve guide clearance problems and oil leaking into the intake system from the guides.

I replace the seats, valves and install new guides so it is a non-issue for me.


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