I recently started a thread on this under ''Wet Sumping''
Since then, MMC have been in contact with S&S on my behalf. I am told that, yes this happens, and the engine should start without problems even if the tank has nearly all its contents in the crankcase. Maybe?
I'm still not sure whether there is a non-return valve of any sort in the scavenge line to prevent this. Most recent advice to me says there isn't. If this is the case, whether the oil level drops rapidly or not could just depend upon the position in which the gerotor pump comes to a halt when the engine is shut down: sometimes it will seal better than others.
