Thanks for your input. It looks to me like there's a hairline crack that extends from the bottom of the tube up about 4 inches. I only noticed it because of the stain from oil weeping through. I guess I'd have to take off the head to get to the tube?
I suppose filling the crack with a little high temp silicone, eg exhaust silicone is out of the question? Might buy you some time while you contemplate your next move...or save up for the repair unless you're confident to do it yourself.
Once I've checked to see how quickly it reappears, I will try using a temporary silicon sealant to determine whether that will help. I don't think I'd do the work myself to remove and replace the head to get a new tube in there, and plan to ride to the dealer for advice and an estimate.
Thanks to you both for your advice. I'll let you know what I learn.
Thanks for the guidance and input. Local dealer says 5 hours labor to remove/replace head to get at the tube, about $600 just labor. Dealer did say original part available, so that's the good news. Local non-dealership Harley specialist shop recommends living with the problem as no or little additional oil observed after cleaning the site. (I've only ridden about 50 miles since cleaning, so that may change.) I'll keep a close eye on the area and address the issue as developments warrant.
I do appreciate the help in thinking this through. Thanks!