Oily exhaust valve

It is definitely oil, as it looks wet in person. The other 3 valves look dry, with the exception of the stem on cylinder 4.

Well then since compression seems good at specifications most likely cause is seals/guides... Would confirm with leak down test but seals would be my gut feeling as the
culprit...

If this is the case and your already in the head anyways... basic head valve job, new OEM seals, new guides and you should be good to go....

Or a complete head rebuild with P&P by Cavanaugh would be the way to go... Of course new seals, guides, springs and possibly valves themselves...

OMR

I just removed my old coils since I purchased new ones and found a crack that ran halfway down the side of one of the coils. I'm hoping this is the reason why my bike has never ran as good as it should have, but it will be a while before I get everything back together to see how well it runs. I'm still trying to make up my mind on what to do. Any idea how much it would cost to get the head rebuilt?

All depends on you and what you want accomplished...

You can spend as little as a couple hundred for a minor valve job, bead blast clean up and new oil seals only or ~ $700 for a total rebuild with all new components plus port & polish...

Or, as some others have done, had the head bead blasted and replaced with OEM seals themselves @ $10 each.

Either way, oil in the combustion chamber, not good...

Accomplish the leak down test for this will give you some further insight as to what may also be wrong such as valves not seating properly. With the compression your getting, seems it would be in spec but you may want to make sure right...

OMR

In case you need it...
Procedure on the right in text...

Personally I would not let anyone near my internal engine parts with a "BEAD BLASTER" those glass beads are really abrasive and will cause problems for your bearings. Get the head "HOT TANKED" instead. I buy my own valve seat cutting tools online, and use "NEWAY" carbide cutters for the seats, and buy new valves for the exhaust and use a Briggs & Stratton field service tool for refacing the intakes. This can also be found online.
Still I would just replace the seals with the head on the bike if leak down test is good, no ring or valve issues. Cheap leak down tester can be found at Harbor Freight Tools or EBAY, $30 on sale with coupon.

You have the links to these valve tools?