2007 yz 450 f motor/head bucket sticking

One of the exhaust valves bucket is sticking any ideas why? Overheated the head or? I tried test fitting without mixing anyone of the buckets amd none will fit easily like they should.

Any signs of galling?

No not at all really

Might mic the O.D. of the bucket and check for roundness. Never heard of one not going back that hadn't been overheated (signs of galling) or knocked.

Go works style and have some made of a super alloy and machine the heads to fit lol

What exactly am I looking for. The bucket looks exactly like the others. What is galling? Marks, marring, etc?

Typically a dulled area where its visibly been rubbing in its socket. Or if its all dulled it may look like a place that's shinier than the rest. Its a sign of being misaligned.

O ok, yeah all five have shiny areas, dull areas and or areas I can actually see wear. some in the head some on the bucket

The most common reason for lifters being hard to remove or insert is that the camshaft bore gets scored by a seizure or partial seizure, and the metal gets "smeared" over the lifter bore.  Try deburring the top corner of the lifter bore with a sharp knife blade or a file.  Then check your camshaft clearance.

Ok thank u i did that and it fixed it. The exhaust cam has a little resistance when you try and move it by hand when it's bolted hand tight. I was worried about that also, I didn't torque it just snugged it to test how freely it moved. So the camshaft clearance to the cam cap or cam bore? I've never checked that but now that you mention it that seems like the whole problem with the sticking bucket

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