03 yz 125 piston

Alright so after years I'm finally doing a rebuild on my old race bike. Check out this piston just wondering if anyone can tell me what's going here or if this happens normally. Thanks


blow by.


normal for a worn piston, ring, cylinder, or all.


Have the cylinder measured so you don't go throwing a piston kit in it only to find out the cylinder is too worn........like I just did. It will run ok for a few hours but then start loosing power quickly.

Edited by RBI

Normal. Godspeed on your rebuild.



By normal...i mean...normally worn out.

Thanks for the help guys

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