There is no said fix. Look at it like this. My bike is a dry sump style oiling system. Wet sump is like a car or the asian type bike engines. Dry-s needs to keep oil off the crankshaft weight throws. NASCAR cars use dry-s so the crank does not drag in the oil. All that effort to make more HP so in a way this engine design had a racing trick going on-wink-wink!
The next part is the oil in the sump tank. How much pressure is on top of the oil in the tank? 14.7 psi. So in a way, there is 1 atmosphere on the oil pump blades. Spread your fingers out and engage the other fingers so they interlock. See the air gap between your middle finger in between the 2 fingers on the other hand? That's how the oil pump works as it captures that little wedge of oil, basically. Those 2 gears spin so fast, it produces pressure within seconds.
The part you can't fix is the oil. Back in the 1950's the army knew oil could be thinned out to a millionth of an inch. So imagine how those pump blades are not made to tolerances to hold back oil. With that said, can you see the 1ATMO snake thru the blades as they have that much pressure happening every second and you let the bike sit? It's just something inherent about the oil winding up in the dry-s cavity and the return is being pulled back into the tank eventually, but the windmill effect inside the crankcase with that much oil, has an escape route just for this.
The crankcase has to have 14.7 psi too, so the breather hose has that dry-s to let the compression bleed off as the air does go past the rings some and there is your excess air. So that buildup too is addressed by the breathing system. I usually lift up my trousers, slap my hands a couple of times and say, well, that takes care of that!
One of our experts chimed in with a perfect explanation...Thanks Sven 
