[chatty katty]

"My first guess was that your rebuilt valves were retreating into your head"

Yes thats what was happening. Don't know why though. My only guesses are:

1. Originally overtightened 4 of the intake valves on accident due to rocker arm play, which caused damage to 4 of the 8 intake valves. Maybe once the valves were originally damaged, they just kept on getting worse, which kept throwing off the valve adjustments. When I took the head off and looked at the valve springs from the side, the worn valves were sticking up a good 1cm higher than the other valves.

2. I installed a 89 gsxr intake camshaft, but kept the stock exhaust camshaft in there. The exhaust valves were all fine so that makes me think the aftermarket intake cams MIGHT have had something to do with it.

I'm not an engine expert by any stretch, This time I am keeping the engine stock and hoping for the best.

[KLR]

Nah, chatty katty, don't eat yourself up over it!

I doubt anyone's advice could have prevented what happened to your head. Sometimes these little guys get in to the works,

and ***t happens!

[crazypj]

I hadn't been following this thread but was just about to post valve sinking into head when I read you found problem.
Its really common on off road bikes and ATV due to dirt ingestion
Suzuki don't use hard valve heads on intakes, they are tufftrided.
The exhausts are stellited though (hard facing material, but its pretty thin)
In either case, lapping valves will probably wear through the surface (particularly on intakes)
Suzuki haven't made 'lappable' valves since 1977 in the early GS750

Just read through from beginning, you lapped valves during re-build.
hope you didnt lap valves second time around or you could be doing a third top end?
PJ

[chatty katty]

" Just read through from beginning, you lapped valves during re-build.
hope you didnt lap valves second time around or you could be doing a third top end"

Lapping? Could you go into a little more detail?

[arsenic]

when you lap valves you lap them with a valve grinding compound, both coarse and fine. You apply the griding compound and move the valves back and forth with a valve lapping hand tool. then you wipe the compound off and install the keepers and springs.