Question: Site A is 301ing to Site B. I want to make each site seperate now. If I remove the 301 on site A can it recover it's value, and any ideas how long it will take for site A to "return" to what it was?
This is largely a search-engine-specific question, but yes, you can remove the 301. If the redirected-from domain still has backlinks, then you may expect to see it re-appear independently in the SERPs within a month or two.
However, some of the threads in the various SE-specific forums seem to indicate it might take months --up to a year-- before it regains anything resembling its former glory.
And of course, the redirected-to site is going to lose the benefit of those links pointed to the redirected-from domain.
I would advise making only small changes to the pages on the redireced-to site for use on the redirected-from domain; Enough to avoid major duplicate-content issues, but not enough to make the SEs think that the targeting of the site is different. If you reincarnate the domain *and* change all the pages, then they'll likely see it as an entirely-new site, and treat it as such.
I freely admit that there are some weasel-words and vague phrases in this answer; Since I don't work in the algorithm development group for any search engine, I can't tell you how they will behave in the future.