It drives

Some times we win.

Jerry

Forgive my ignorance. But why would you need to replace the adjuster screws? How can one tell if they go bad? How would they go bad? If they wear out from contact can't you just simply screw them in some more?

Bob Hoover explains why here:

Make sure that the cylinder head nuts are properly torqued! I usually check these before the valve adjustments, at least the lower ones.

I might have to try Bob Hoover's information one of these days. ;-) I used to keep new adjuster screws in stock, but now I would not know where they are anymore. I just don't see air cooled much anymore. :-(

If you look at a new one, you'll see that the tip that contacts the valve stem has a convex surface. Over time that surface gets pounded down, and of course when you adjust the valves you turn the screw enough that it probably contacts an unworn part of the screw tip, but eventually the screw will get pounded flat on the end. Once that happens you should replace the screw. Mine were flattened and showing some pitting on the friction surface, so I replaced them.

Chris