> A ticking progressed to a knocking my final trip of
> last summer.sounds like front end of the left side case.

I have an '81 air-cooled, non-California.  It ran too
hot around Bishop and Lone Pine one September and started
knocking.  I drove it home to Boulder.  Teardown
revealed the noise was piston slap.  The cylinders were
all scuffed up.

Cause:  poor sealing of the engine tin to the body, so
heat was coming up to mix with the cooling air, which
then didn't.

Good luck!

Richard