If you have the exhaust valve set at .00, you will have problems down the road. That clearance is to small and will become even less as the valve heats up and expands. Air bubbles in the oil were caused by running with the valve cover off.
Thanks for confirming my bubble-assumption.
I have the exhaust valve at .03 (not .00) ... do you still think that is too tight and I need to back it out a bit again? (sniff ... but it ran so good - and I ran it for about 1 hr, mowing)