Any ideas on what has to happen next? I have no idea how they got this way. Update: after getting everything apart and scratching my head awhile, I think it's possible that the discoloration is dirt and stuff that is stuck to oil that seeped out of the cracks. It's not on the other side of the intake, but neither are any big cracks. Oil residue is everywhere inside the adapters and on the mating surfaces of both heads. Drawn in from the breather tube at the air filter, no doubt. Not sure if it's a feature or a bug, but this seems to me to at least be a possibility.