David,
I have owned many bikes with the dreaded wet-sump-problem and have never drained the crankcase prior to starting. However, after starting, I do let the bike idle for several minutes, alowing the pump sufficient time to scavange oil from the crank case and circulate it back to tank.
There is an excellent procedure for checking/lapping the oil pump in various Norton work shop manuals. If you don't have this information in any any of your manuals or documents, let us know and one of us will get it to you.
Jason