Worked on the bike yesterday, then karate and a busy day at work today, so no time to post until now.
When I got the parts back from the machine shop, I didn't really compare what one head looked like vs the other one. Â I looked at them, and they were shiny and clean and pretty. Â lol
So yesterday I took the right side head off, put it on the bench, then took the left side off and set it next to the other one. Then I got to looking at them. Â Hmmmm.....
This is what they look like side by side:
Problem head is on the right. Â You can see where the intake is seated lower that than the one on the left.

But.  This is what it looked like before I sent  it off:

And now: Â I cannot tell if the recess is any deeper.

Now we look inside:
Left side:

Right side:

You can clearly see the valve guide on the left head is pushed further onto the valve stem than the one on the right.
And measuring the intake spring heights, the problem (right side) head is roughly 1/8" taller than the left side.
I thought this might be related to the unleaded fuel, but from what I can tell, its only a problem on the exhaust side and normally not on the pre-1979 bikes. Â But I don't know. Â The bike was having some leak down and compression issues on both sides, which is why I tore it apart int he first place. Â So, the question now is, can it be fixed? Â
Would pushing that valve guide further onto the valve stem solve the problem? I think maybe not, as the guide is just a sleeve and has nothing to do with the length of the stem. And the valve cannot be pushed any further in as then it won't seat properly. Am I SOL and I should start shopping for a new right side head?
