Yz250f Vales

wato
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wato
Im in the process of changingbthe piston on our 2021 yz250f . I have the cylinder head off and the valves out , firstly what do i look for to tell me the valves need changing ? Secondly if the valves are ok can i clean them up the old way in a drill with fine scotchbright to clean them ? Bearing in mind theybare titanium..The engine has done 40hrs . Tia .
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murph783
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murph783 2/16/2022 6:39am
2/16/2022 6:39am Edited Date/Time 2/16/2022 6:40am
Check the shaft to make sure it’s straight, look for pitting on the faces, check around the tip for any hairline cracks.

Now as far as cleaning I’ve always been told no with titanium…but I do it anyway. Not recommending it but I haven’t had issues
YZed250
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YZed250 2/17/2022 9:48am
2/17/2022 9:48am
wato wrote:
Im in the process of changingbthe piston on our 2021 yz250f . I have the cylinder head off and the valves out , firstly what do...
Im in the process of changingbthe piston on our 2021 yz250f . I have the cylinder head off and the valves out , firstly what do i look for to tell me the valves need changing ? Secondly if the valves are ok can i clean them up the old way in a drill with fine scotchbright to clean them ? Bearing in mind theybare titanium..The engine has done 40hrs . Tia .
Check for leaks.
As murph said, clean and inspect everything carefully, especially the seats and valve faces.
I recall referring to this tech tips from Fast heads when I did my KTM:
https://fastheads.com/2018/11/itsallinyourhead
mx724
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mx724 2/17/2022 12:43pm
2/17/2022 12:43pm
Not to hy-jack this thread it is somewhat on topic. So what are you guys using to clean the valves?

Ive seen Yamaha makes a combustion chamber cleaner?

Lucas oil makes a degreaser? Obviously want to be cautious here with the coating on the valves.

Any suggestions appreciated!
YZed250
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YZed250 2/18/2022 10:41am
2/18/2022 10:41am
mx724 wrote:
Not to hy-jack this thread it is somewhat on topic. So what are you guys using to clean the valves? Ive seen Yamaha makes a combustion...
Not to hy-jack this thread it is somewhat on topic. So what are you guys using to clean the valves?

Ive seen Yamaha makes a combustion chamber cleaner?

Lucas oil makes a degreaser? Obviously want to be cautious here with the coating on the valves.

Any suggestions appreciated!
There are lots of ideas if you search online. Last time, I used Yamalube carburetor dip and a nylon brush. It took a few applications to soak most of the deposits off the head. Final cleanup was using deagreaser and the brush, and a scotch bright in the compression area of the head, only.

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