My son was home from college and was anxious to see what was going n with the new CRF150R (that doesn't run), so we started ripping it apart.
First thing we found after removing the cam assembly and lifting off the spring were the valve retainers and tiny shims laying loose in the head (some visible in the right lower corner in the photo) -
The tappet or lifter had a hole punched through it from the valve stem -
One of the intake valves was bent and jammed open -
Where the valve hit the piston -
We did figure out that when the cam slipped and the timing went off the intake valve stem got punched up thorough the tappet and into the cam, where it ground the cam lobe down. Not sure why the other intake valve didn't do the same, but everything there looks fine.
The kid that sold it to me probably knew things were a lot worse than he let on, but I did get it for about 1/2 of a regular price so I can't complain too much.
Ordered a new piston, pin, rings, cam, gaskets, valve, tappet, and a few other pieces that should be here in a week or two. Spent about $400 so far including the factory service manual (which is absolutely required for working on it - IMO)
Overall not as bad as it could have been (but it ain't running yet...).