I know things... A lot of things.
Join Date: Feb 2015
Motorcycle: GSXR 750 K4
Re: Oil Question
What you report sounds like a magic trick, so the only explanations I can think of, short of a major leak, is that you either aren't checking properly (i.e. the bike isn't entirely straight), or the sight glass isn't very clear and you can't see the level, or you overfilled it to begin with and mistook an entirely full sight glass for an entirely empty one. The latter seems the most likely of the lot. Note that you're right in being wary of running the engine with too much oil as it can have undesirable effects, ranging from minor, such as expelling oil into the airbox, through the breather hose, to more major, such as blowing engine seals, due to the elevated pressure inside the crankcase.