whats a plane bearing?
sometimes you get lucky, if the oil pump starts sucking air or froth its the cam bearings in the top of the engine that get oil starved first, or if you get gas in the oil and it gets really thin, it can supply oil to the main bearings on the crank, but does not have enough pressure to reach the cams.
but usually by the time you hear something knocking, all your bearings are gone, including the transmission
with no oil pressure zero warning light on most of these bikes, you really do have to check the level every morning. Thats why they made it so easy with the sight glass - just need a little mirror on your keychain.