This is an idea based from the breathing on the BMW Rotax twins.
They have holes on the outer edge of the gear for the water-pump and the gear sits on the end of the inlet-cam.
CC pressure exits the center of the cam without any oil in the air-box.

The idea is to let the engine breathe thru one of the cams, thereby use the rotation to fling the oil out of the air.
(preventing oil mist coming out when going fast over an extended period)

This set-up is just to separate the oil from the air (thru the cam).
Air comes into the cam thru an opening as far from the center of the cam as possible to let centrifugal force fling the oil out of the air.
Then, the air exits the engine thru the center of the cam via an extension through the cam-cover.
The cam is to have a fixed tube straight through the cam-cover and into the cam.
And then a seal on the end of the cam where the tube goes in the cam cover.

From there the air is fed through a reed or umbrella valve to atmosphere.