Hi Sparker,
Gently pry it off working your way around. Once off don't clean up the old goo, just leave it in place, clean the oil off well, re-silicone it and put it back on. Having said all that if you mangle it beyond serviceability they're actually fairly cheap, about $12 from your Honda dealer.
Before pulling off the cover and checking valve clearances etc, i would re-set the governor as that can cause them to hunt if they're out of whack.
Cheers, ted
