OK here's a question for y'all. Check out these
pics of my valves (warning: full rez versions of pics are 2MB each). These are off of a CB750F3 with either 15k or 45k miles; the history of the bike is a bit murky.
Were the tips of the F2/F3 valves bevelled originally? Looking at intake valve #4, it hardly looks bevelled at all - and has the least wear in the piston/cylinder too - telling me it was either not gapped right, not firing right, or something else. On the exhaust side, all 4 have bevelled wear, but again #4 has less wear than #1 (see the close-up comparisons taken on graph paper for better side-by-side.
I'm trying to determine if a) this is normal, b) if I should try and resquare the ends, and c) if so, how much is "too much" to take off to try and resquare the ends. Valve guides and seals are already slated to be replaced. I don't want to buy new parts just to buy new parts, and don't dread taking the head off again in a year or two to replace them - but I also don't want to risk catastrophic engine damage or waste my time cleaning these if they're shot.
Intake stem tops:
Intake #1 (L) and #4 (R):
Exhaust stem tops:
Exhaust #1 (L) and #4 (R):