I checked the pump's clearances (on the first rebuild) and primed it to get the oil moving through it. Clearances were great. Where I think I screwed up was a combination of things: Because I was busy with work it took about a week or so before I was able to do the valve clearance adjustment. Between taking a few rotations to find TDC for the cam/timing chain instalation and then taking a few rotations to find TDC to do the valve clearance, I must have drained the oil pump. Oh, again, I hadn't put oil in the bike prior to doing the valve adjustment. Yes, stupid, but not totally unthinkable (until now). From now on I will always loosen the top nut on the oil feed tube at the top end to check for oil preasure, before I take off down the road. New piston and cylinder are on their way though. I have another question about other potential damage from seizing which I'll post in a new thread. Thanks for taking it easy on me though. I very fragile right now.