i bought a head with valve train attached. as i'm cleaning it up, i see that there is some sort of discrepancy at the exhaust port, where the header contacts the head itself. it appeared to be carbon build up, with a shiny surface. it turned out to be the metal itself, flaking off. there is material missing on the flat surface that would otherwise form a seal with the header pipe.
i used a jewelers' loupe, and saw that there was definitely metal gone, exposing some sort of chain-link material.
the spot on the bottom of the port, where the cut-out is, has the worst damage, but i can see the chain, or the barest impression of it, along most of the surface.
i'll find my kid's digi camera and take some pics, but i really doubt that the camera and my photo skill will show what i'm talking about.
eddie, if you're reading this, have you ever seen what i've described? i think i might try to source a copper gasket, like kz's used to use, and see if that might seal it up. i haven't even put it on the bike yet, so it may be a non issue, but my old head certainly doesn't look like that, even with the magnification.
