It's alive!
...so to speak, as I don't have the carbs for it...
It oiled up after sitting with oil in the tank, but with no oil filter housing on it (because I forgot to paint it, had to do that these last 2 days). What I noticed that was a good sign: there was a slight dribble of oil coming out of the lower port in front of the engine, the one that feeds the oil filter from the pump. It's been sitting 3 days with oil in the tank while I found a new battery for the garage, and had to charge that up last night.
I might mention this aside re: lead-acid batteries: when you get a new lead-acid (this includes AGM types) battery it has a 'factory charge' on it, which was a dry charge applied before acid was added to the cells. This lets the battery be safely shipped as it cannot discharge much of this power if the terminals are shorted, thus reducing fire hazards. But, when acid is added this charge drops to about 60%-70% of the battery's full capacity, enough to start whatever vehicle it will power. BUT...if the owner does not first charge the battery to 100% while wet BEFORE the first heavy discharge (like starting an engine) it creates a chemical limit that prevents the battery from being able to store 100% of its total capacity. Over time, this limits the battery's life, too (which is probably what happened to my last one, as I didn't get it new myself) because the lead decays from the first discharge point to end-of-life, and the first large discharge determines this lifetime. So, when you get a brand-new battery, charge it until it climbs out of the normal range-of-voltage (which would be typically more than 13.6 volts in these bike-sized batteries, when it will quickly then climb to 15 volts) and you'll be rewarded with a longer life.
NiCd and lithium batteries are a little different, and those can suffer from overcharging, which similarly limits their lifetimes and full capacities.
...a little something I learned during my NASA spacecraft training regarding batteries, of all types...
I'm supposed to get the new/old/junky valve cover this week, so I'll cut away the top of it to show the oil feeding to the rockers. Then I'll take some more pix and attempt a video to post here. Has been a long slog, but it's finally done and makes a running sandcast possible! Very cool.