Harley Davidson Evolution Oil Breather

The internal passages on Harley heads need to breathe and the oil drain holes usually found in the corners of the rocker plate must be open and large enough for air and oil to move and drain.

Harley davidson evolution oil breather. HARLEY engines excluding early engines with total loss oil systems manufactured up until 1999 used some form of timed breathing to scavenge oil from the crankcase and deliver it to the vicinity of the return oil pump so that it could be sent back to the oil tank. In you 89 model the crankcase breaths from behind the oil pump through a tube that runs to the backside of the air filter assembly. My 96 Softail is puking massive amounts of oil from the breather tube.

This was done in an effort to reduce the amount of oil that gets into the air filter. Fast Free shipping and the best customer service. Ever since the introduction of the EVO engine with breather heads and the use of high flow air cleaners breather blow by has been an issue.

In the following drawing the top arrows are pointing to the oil return oil. Rick since 1994 Harley has used what we call a head breather system in that the crankcase breathers are located in the heads. Simply thread into place for a clean looking breather option.

As a result a fine mist of oil in the vented crankcase air condenses in the air cleaner and must be cleaned out from time to time. Features an internal oil baffle that allows the oil and air to separate. Top breathing engines breath or vent through the top breather bolts which are threaded into the heads of a Harley Davidson motor.

An internally broached allen allows for a quick and hidden installation method with the stainless breather element and circlip finishing the job. 89 Harley FLTCU oil coming from the crankcase breather tube and. The evolutionâs external filter requires two oil lines.

The dark circles between the two sets of arrows are the umbrella valves. As of 2011 the Sportster remains the only model from the Harley-Davidson that still employs the Evolution engine in both 883-cc and 1200-cc. Radius breather bolts from Lowbrow Customs feature an innovative design with 5-ply sintered stainless steel mesh providing the proper breathability for your motor while keeping a slim profile and a completely custom look.