When was the last time you did a top end? If it was fresh before the hare scramble, that little bit wouldn't wear it completely out! I just meant 125's will wear out topend's more FREQUENTLY than a larger displacement bike. It really depends on how you ride. Hard, high RPM riding will require frequent ring changes (matter of hours), casual-moderate riding will require less frequent (couple of months).
My YZ80 is harder to kick over than it was when i got it. It doesnt seem like it has any compression. I have been fouling plugs and i was wondering if the quote you posted goes for the 80ccs too?
The smaller the displacement, the more rev's needed to make competitive power, so yes pyrofreak your 80cc top end is probably just needing a top end rebuild.