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94 XR250R Sticky exhaust valve?

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My XR has been providing me lots of fun lately..  First an issue with power cutting out, and now the engine started making a very loud ticking sound.

Tonight, I started inspecting the engine.  With the spark plug & all 4 valve access caps removed, the engine is very difficult to turn via the crankshaft on the exhaust stroke.  I can even hear some creaking/groaning on the exhaust stroke.

It also smelled like burnt oil when opening the valve access caps & it looked pretty dry up near the valves - not much oil was up there.    Not sure what is normal for these bikes...  Come to think of it, I've noticed a bit of white smoke coming from the bike while it was running too.  :facepalm:

I had adjusted the valves when I bought the bike in October.  The intake valves were .04mm and .05mm (spec is .05) and the exhaust valves are ~.11.5mm (spec is .08mm).  Today, all valves were much looser than they should have been.  .09mm intake and .15mm exhaust. 

Was hoping to get some outside opinions before I start tearing it down.  

I also am thinking it would be a good idea to warm up the bike one more time and do a compression test and/or leak down test to check the condition of the rings.   Though the bike was bored out to 280 by a previous owner several years ago, so I'd have no clue which rings to get..

Edited by jamesm113

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I performed the compression test tonight.  Got 145PSI dry, 177PSI wet.  Spec is 170.7-184.9PSI dry, though the Haynes manual says 171-185 with 1.0mm (:jawdrop:) of valve clearance.  I did not adjust the valves, so the values from yesterday are still current (.04-05mm intake, .11.5mm exhaust).  I'm leaning towards leaving the piston be.

 

Here's a video of the noise:  

 

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