My 97 rm125, what could of caused my piston to look like this

I tore my bike completely down for the winter and found my piston to look like this. Anyone know what could have caused this????    
1997 RM125
(Thanks DirtJumper)

Are you referring to the shiny patches, or the dents around the edge?  
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The King Of Crumpets - Crumpet Boy!

- 1991 RM125

oh yeah, i got the bike like this also. What about the head, i know all the tiny marks are from being blown up before, but what about the flat spot on the upper part in the pic  
1997 RM125
(Thanks DirtJumper)

i am refering to how bad it's tore up. I cleaned the piston up to see what size it was  
1997 RM125
(Thanks DirtJumper)

Looks like the bearing had some slop. and then someone filed the head to remove some edges.  
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"Every time I start thinking the world is all bad, then I start seeing some people out there having fun on motorcycles. It makes me take another look." -Steve McQueen

i think the head is shot but i'm not sure on that one.  the motor was kinda noisy, eveen for a 2 stroke  
1997 RM125
(Thanks DirtJumper)

If some of the holes are new I would check the play in the bottom end also.  
__________
"Every time I start thinking the world is all bad, then I start seeing some people out there having fun on motorcycles. It makes me take another look." -Steve McQueen

not quite sure if any of them are new. this is the first time i've tore it down  
1997 RM125
(Thanks DirtJumper)

aaronjohn20:
not quite sure if any of them are new. this is the first time i've tore it down

The dents or gouges are from some metal pieces thrashing around.  The question is from what and are any still hiding somewhere?

How does the cylinder walls look?  
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Dave H 2006 YZ250
(2008 YZ 125 son)

the cylinder wall actually looks pretty good  
1997 RM125
(Thanks DirtJumper)