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Exhaust cam binding up?

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I'm trying to finish up a rebuild on a 2005 RMZ450 that dropped a valve into the cylinder. Damaged head, bent connecting rod, etc. Now it's finally going back together and I find the exhaust cam binds up on me as soon as I get the journal holder tightened down even finger tight.

 

The intake cam spins perfectly find even after the bolts are torqued. What should I suspect is the culprit here? The journal holder? The head? The cam?

 

This engine has a kind of shady history, so that doesn't help. It had a "valve adjustment" done by some backyard mechanic. 20 mins of riding after that, and the valve dropped. During the rebuild I found that the top chain guide was missing which very possibly conmtributed to the valve meeting the piston. Now I've noticed that both journal holders have had heli coils intalled. So at some point I assume someone way overtightened the valve cover bolts, stripping them. Could the heli coil install have warped the journal holder? I'm completely lost, and I'm really beginning to resent the moron that worked on this. No wonder it blew up! I just want this done. Please post any suggestions or theories you may have.

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make a slight chamfer on the cap edge and head edge where they part I have found that they protrude enough to cause the cams to bind

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