Continued observations while I observe three different cases/tests (the last one may be the most interesting, if you want to jump ahead):
(277° crank)
FIRST Case: The tensioner at about 12mm from lock nut surface to end of the adjuster, threaded section (NOT INCLUDING the pin).
This was the same adjustment while motor running, horrible clicking sound, yesterday's video).
Turning the motor by hand this morning, I realize the clicking occurs as each of the four valves is on it's closing stroke.
Video Just an example - focusing on #1 cyl INTAKE valve movement and the click as it is on it's closing stroke. You can hear 2 of the four clicks occurring as I turn the crank (before this valve opens.
It seems the sound is made when the cam chain adjuster pin hits its' "hard stop" as it is being forced outward (toward the rear wheel).
When the pin clicks and I am able to measure the distance of movement beyond the adjuster's threaded section, the amount of exposed pin is about 3mm. The only time the pin extends out this far is when it makes the click. Putting my finger on it, the click is simultaneous with the motion of the pin "stopping". It rapidly pulls itself back inward as I turn the crank.
Following the pin INWARD, I get about 10mm of motion from the end of the threaded adjuster section. Total travel then - is loosely 13mm.
SECOND Case: Adjusting the tensioner OUTWARD, backing of tension, to about 20mm. The clicking still exists, but seems to be reduced in volume (or is it?). #1 cylinder INTAKE - is still loudest. Total pin movement and the amount that it sticks out and all, etc - is about the same as the first case.
Third Case: Next I removed the Tensioner pin completely.
Now, there is a sound (more of a clunk than a click) - and equally present as each of the four valves as they start to close (at least - at that "position" during the full cycle / hand cranking).
What the heck is this? Sounds like something hitting softer material...