So I took of springs from the head - 1978 CB750F. Here is what I found:
1. Leak test was good, no leaks whatsaver.
2. Valves have some play, sttill need to check it against HM book specs.
3. All intake valves are mushroomed to some extent, I was not able to pull them out by hand.
4. #2 intake is the worst, #4 is second worst.
5. The cam is looking good, same for arms.
See pictures for details - the #2 indent is 0.8mm deep.
And my questions are:
1. Why is there the indent?
2. Is it ok to grind it off and reuse the valve?
3. How to prevent it from happening again?
4. Should I replace tappet screws?
5. Should I replace valve guides anyway since it is F and guides will go bad no matter what?
Any insight is highly appreciated.
