I'm confused about the maintenance and annuals on an experimental I purchase.

[Marc Zeitlin]

Unfortunately...

Why "unfortunately"? Do you think that E/AB aircraft should be subject to all the rules that certificated aircraft are? And if so, how would that even work, without TC's and specifications? What about one-off aircraft?

... it's not the law because as you stated earlier, the applicability section of Part 43 excludes E/AB aircraft and that exclusion includes 43.11(a)(5).
That's why the operating limitations for an E/AB aircraft include a paragraph on how to perform and sign off the required inspection. Absent that, there would be no rules to follow.
I'm sure the others will point out there are no airworthiness standards for E/AB aircraft, ergo, they can't be found unairworthy.

You just did :-).

I'm with Marty on this one for the reasons he states - Part 43 exempts E/AB aircraft.

In any case, however, 43.11(a) says:

"The person approving or disapproving for return to service an aircraft, airframe, aircraft engine, propeller, appliance, or component part after any inspection performed in accordance with part 91, 125, Sec. 135.411(a)(1), or Sec. 135.419 shall make an entry..."

So, as long as I'm not "disapproving for return to service" the <item in question> I'd argue that the requirement for a logbook entry doesn't apply. And "unairworthy" blah, blah, blah per above.

If I wanted to put a list of "discrepancies" (as noted in 43.411(a)(5) in the logbook, that would be a possibility (if the owner was OK with it), but none of it is prescriptive. The owner can take the plane (still legal to fly [however un-smart it may be] until the current CI expires) go home, fix it (or pay someone else to fix it) and then bring it back to me to show me the discrepancies are fixed, and I can then sign it off. Or, he can pay someone else to inspect the plane again, if he didn't like me or what I told him I thought needed to be done. I cannot ground his plane - I can only refuse to sign off a CI if I deem it unsafe. Now, that's the same as grounding _IF_ the current CI has expired, which is why I said that folks shouldn't wait until the last day of the month to get their CI's signed off :-).