Can you "hear" your valve train?

[the cyclops]

So what did it end up being?

[Sasquatch]

It ended up being a good sized flaw on the exhaust cam gear.  The side of one tooth was peeled down.  Hard to describe without seeing, but I did not take any photos.  I ground it down smooth, no more noise.

I plan on replacing my cam chain and one of the rails this winter out of a precaution.

[Stretch]

Abnormal wear... improper manufacture / heat treatment?  Funny to have it just in one spot like that.

Anyhoo, glad you got 'er sorted out.