So, at around 3800 miles I checked the valves again and they were within spec, but my compression was down to 85psi cold. Should be 100psi cold. Since I have a big bore kit on the way, and hopefully a new head as soon as CSC gets back to me... I decided to take the motor out and see what I'm working with.
It was actually pretty easy. The whole motor came out of the frame with little drama, and it was light enough to carry to the workbench with my arms outstretched - so as not to stain my shirt with oil and grease.
I pulled the head off and took the exhaust valves out, and... well, there's not a lot of damage, but there is damage. One of the seats is showing scoring and lines, and it's not a bright and shiny ring all the way around like the other exhaust valve is.
The valve itself looks fine though.
If you look closely at the seat in the head, it's not perfectly round. There are areas where the seat is wider and where it's narrower. And the damage I'm seeing is at the narrowest part of the circle.
What are your thoughts on this? I mean, it's not obvious catastrophic damage, but then, the bike still ran fine, it was just a little low on compression, and the exhaust valves kept tightening up. Unless the seat is in there crooked (which it very well may be), I think I might have been able to get away with lapping the valves and reinstalling the head. (But with a new one on the way and all the effort to get the engine out of the frame, I'm not wanting to take that risk)
Charles.