progress: adjusting the tappets

Here I am adjusting the tappet clearances with the world's most ghetto tappet screw adjuster. Small vice grips + #10 x 3/4" square drive pan screw.  The square drive fits the tappets perfectly.  It worked - not very well, but I was too lazy to go hunting for a piece of dowel like this guy suggests.  The procedure is pretty simple and pretty frustrating: undo the locknut, screw the tappet in or out until the .006" feeler won't slide in and the .005" one will, and crank the locknut down tight - after which both feelers will go in, or neither, and you have to do it all over again ad nauseam. And when you finally get it right, you get to repeat the process another fifteen times.  And this every 12,000 miles! Hydraulically self adjusting valves (like on Harleys and Moto Guzzis) are the much mo' betta' way, in my opinion.

The reason I did the adjustment this way is that valve clearances, especially on red-hot exhaust valves, tend to tighten over time, and the purpose of checking the valve clearances is not to check for loose valves but to check for tight ones.  A tight tappet will force the valve to stick open slightly,  there will be no metal-to-metal heat transfer, and the valve will fry.  Valves are 30 dollars apiece. So you want loose valves at the outset, not tight ones.

Also the valve adjustment range for the GS is very narrow: .004 to .005 inches, so checking them at the specified intervals is important!