To my surprise, I discovered not much carbon build-up on the pistons and combustion chamber. Surprise for two reasons - one, it has a decent amount of miles; two, the bike was pretty darn neglected in all other aspects prior to my buying it.
The cylinder walls look absolutely perfect and the rings don't leak even after 90 minutes of soaking under WD40. (I stopped for lunch and a quick ride on another bike to come home and find WD40 still pooling happily on top of the pistons.) Furthermore, the valves all seem to seal perfectly (as similarly tested with solvent while the head was sitting flat in its normal orientation).
The engine had what appears to be a three-layer metal head gasket.
Is this the stock head gasket?
