OK guys, I am having a brain fart. Checked my valves yesterday and all were tight to the point of needing new shims. I pulled the shims and all four were 260's. Used the shim calc and it told me I needed 250's to put everything at the loose end. OK, here is my question: Exactly how do the valves become tight? My poor brain wants to think the opposite, in as such as something wears it becomes looser. "don't laff too hard", but can someone explain this for me in a way a first grader could understand it, LOL. My buddy is having the same brain fart too. And thanks for tolerating my ignorance.