Hi,
I have been makeing a few carbon parts and the finish has been quite good for hand layup. I don’t use any gel coat before so  in order to add the UV protection, I have been coating them in XCR. However, no matter how much I rub them down, clean with a degreaser, the xcr always fish eyes. 

Any thoughts on what I can do to prevent it?

When you say 'degreaser', what exactly are you using? Products like engine degreasers are completely unsuitable for cleaning parts prior to coating. Needs to be a product intended for this purpose. 

Also, what grit are you sanding with? Epoxy needs quite a rough key to adhere well, I personally wouldn't go any finer than 180 grit.

I also wouldn't be using XCR resin for UV protection. It may be relatively UV resistant itself, but I highly doubt it has any UV blockers to prevent damage to the resin underneath. You really need a polyurethane topcoat for this.