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Piston Question

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I'm getting ready to put a new piston/rings in my '09 yz250f (after 200hrs).  I got the new OEM piston in the mail today from RM ATV/MC and there's some imperfections on the 1st, 2nd, and bottom lands.  I can't decide if it's porosity, galling, or just oxidation.  I cleaned it with alcohol and SOS pad and can still catch a fingernail over this area.  Should I run with this or get a replacement from rockymountain?  These pictures are all of the same area.

There's also some sharp burrs on the skirt.  Should I file these down with a diamond file before installing?

IMAG1501.jpg

IMAG1492.jpg

IMAG1497.jpg

IMAG1498.jpg

IMAG1487.jpg

Edited by yz250f_spud

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You should never have to debur a piston, and I wouldn't except a piston with any kind of defect (that's just asking for trouble). My guess is that since it's for a '09 it's been sitting around somewhere for a while, and got banged up. 

RM customer service rules, so I'm sure they'll swapped it out, no questions ask. 

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2 hours ago, jmfreeman535 said:

My guess is that since it's for a '09 it's been sitting around somewhere for a while, and got banged up.

yep sitting around - looks like corrosion or rot has set in

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RM ATV/MC is great with returns so I am glad you got it figured out.  Word of caution though, I don't think I would try to clean any piston with scotch-brite or any abrasive.

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