I opened up Mad Hammish to fix an oil leak.  At first, the infamous plug cap leak was suspect.  Pulled the head cover, and noticed very little sealant between the cylinder and head cover.  That would explain it as well.

Started cleaning it up, and noticed.. this:


and this:

and this:


Now, none of those cracks appear to go all the way through.  There were some spider cracks on the outside, but not in the same location as the ones on the inside.  
None of the walls of the bolt holes show cracks.  No cracks in the cam journals.  No cracks in the walls of the rocker arm shaft holes.  No cracks in the mating surface.

I tried to get some pictures of the outside, but nothing showed up very well.

Anybody ever see anything like this before?  
This is the first time I had the head cover off Mad Hamish, and I don't remember seeing this on Thumper from way back when.

All I can think of is someone may have over torqued the bolts at some time.. but the bike only had a couple thousand on it when I bought it.
Maybe the PO would know something.

Am I worried about it?.. not really.
The only think I could think of doing would be to coat the inside with JB Weld in case there is a leak, but I think that could cause other problems if it ever flaked off.   I might do something similar to the outside though.

Every head cover I have or taken off has similar cracks.  I believe it is a manufacturing biproduct.  
Never had an issue with any of the head covers due to these little cracks.

Totally normal , casting flaws , nothing to worry about , caused by rapid cooling in casting process

Thanks for the feedback people.
I kinda figured that it wasn't an issue, but I don't crawl inside these things anymore than I have to.
Ride 'em as much as I can.. Fix 'em enough to keep riding