At our first race this year I had water in number four.Didn't really think anything of it,just thought the headgasket blew.Anyway got it apart and it was a rust hole right in the middle of the bore.That really torqued me as I had just freshened it 3 races ago.

I ended up with 2 sleeves. Another cylinder had what I thought was a "funny mark" so instead of messing with it I had them knock it out.

So in my case both cylinders had one tiny little rust pit. Machine shop said they never hit any water and they wailed it out to 4.2-something for the sleeves.I figured it was air bubbles.

Gotta figure these things have been rusting fo 40 years now.It sucks I know