[Dave at Pelican Parts]

The common things to do are to either run the combined vent hose to a catch-bottle (illegal just about everywhere, BTW, just like running it open to the atmosphere), or to run the hose to a "breather box", which separates out the oil from the vapor. The oil then goes back into the case, and the vapor and air into the air cleaner of the carbs (if there is a fitting for it).

--DD