Yeah, I was worried about the pump losing prime so I drained the oil then put the plug back in and filled the engine with 3 qts. THEN I removed the oil filter, filled the new one as best I could and installed it.
Started the bike and the oil pressure came right up. I let it run for a minute or so then shut it off and topped the oil off a few minutes later. Interestingly, my bike took exactly 4 quarts to the high line of the window. That's certainly convenient.
I ordered a 16T front sprocket just now. I'll let you know what I have to go through to get the old one off. We have BIG air wrenches if required...