Grabbed the head from the box I immediately stuffed it in after removal, and noticed something I had missed. This:
Well, shit. It's on the exhaust side, I assume it lost a battle with the decompressor, here's a photo with cam in place:
Decompressor looks ok, spring intact. Looks like steel is victorious against aluminum. This add to the jumped timing, bent valve theory?
I'll inspect the cam more after work (should have brought it with me) but I think my best move is gonna be replacing the whole engine. It's just the female stud for the valve cover bolt so maybe I can just clean it up, who knows. The only reason I'm keeping this damn bike is for a ride next month that I really
don't want to bring my WR250 on (way too much road, going with 990's and 650's). I've already got a 685 on order from Eagle Mike so there's that... If I have time, I'll continue digging in order to provide yet another documentation of one of these things blowing up. I'm kind of curious how the inside of the case looks, but first priority is getting this thing going.