I recently came upon some pictures of the crank case vent oil separator I've been looking for, right out of the box...
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And out of the box...
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It is up for sale currently, I took it from their sales page.
I'm seriously thinking, however, of tapping the hole and adapting a water separator used for irrigation for the purpose.
In the rat tradition, I was thinking a beer can and steel wool would be more appropriate for my particular steed... but it wouldn't work for me, I'm a teetotaler.