Patent ID: 6672294
Filing Date: 2004-01-06
Classification: F01M

Abstract:
A box-shaped housing having a floor, walls and a cover enclosing a chamber surmounting a motorcycle engine cylinder and connected to receive a stream of breather air from the engine's crankcase carrying lubricating oil as a mist, said housing providing an oil-separating escape vent path connected to deliver separated oil via an exit oil passage directly to the crankcase while sending the breather airstream separately to a filter on the carburetor, comprising in combinationan oil separating enclosure protruding from a wall of said housing into said chamber above the housing floor thus defining a slot; said oil separating enclosure defining a first elongated oil separation chamber and an adjacent second elongated oil separation chamber; a plurality of upwardly directed vent passages connecting said slot to the interior of said first elongated oil separation chamber in said oil separating enclosure; a partition incorporating a central lip portal between the first and second elongated oil separation chambers; a groove formed in said cover overlying said second elongated oil separation chamber remote from said lip portal, opening into an air passage formed in said housing connected to an air conduit formed in said cylinder head connected to return said breather airstream to the carburetor; and drain hole means connecting said elongated separation chambers by way of said slot directly to the crankcase, whereby the breather airstream propelled by every downstroke of the piston travels successively through respective transitions between the chamber, the slot, the vent passages, the first elongated oil separation chamber, the lip portal, the second elongated oil separation chamber, the cover groove and the air passage, and the airstream, encounters a change of direction at each said transition, producing a zig-zag labyrinth path traveled by the airstream, causing oil mist droplets entrained in the breather airstream to be deposited by their momentum on the interior surfaces of the air separating enclosure and to drain downward through said drain hole means and said slot for return directly to the crankcase.