DanGill wrote on 01/25/08 at 06:12:48:By the way, Reelthing responded to say the clearances get larger with time and wear, and I got a response on another forum that said they get smaller. Not that I doubt you, Reelthing, but can someone else confirm that for me? The clearances were under spec when I intially checked them, which means either they became smaller with wear, or that they were improperly adjusted in the first place. I'd like to know.
It varies on different bikes and cars. On most bikes I've found that inlet will open up with wear due to valvetrain friction - on tappets/cam/followers/rocker arms (irrespective of whether it's adjustable rockers or bucket and shim). Anything with rocker shafts will wear more/faster than bucket and shim.
Exhausts sometimes also open up but sometimes close up because valve seat recession is faster than valvetrain wear.
There's no absolute rule, and I'm not sure what the LS does.