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-   -   crankcase breather blowing oil (https://www.hdforums.com/forum/oil-archive-no-new-posts/123228-crankcase-breather-blowing-oil.html)

weewanreefer 06-23-2007 02:32 PM

crankcase breather blowing oil
 
have just had the engine out of my 1980 FLH to have the frame powder coated.After putting the engine back in i was turrning the motor over with the spark plugs out to feed the oil through the engine when i noticed quite a lot of oil cumming out of the crankcase breather,will this clear or should i start to panic.

Seaquester5 06-24-2007 02:16 PM

RE: crankcase breather blowing oil
 
my 88FXRS does that when I shut down if the bike has not been ridden for several months and then just clears itself up.Never got an explanation for it starting to leak or for curing itself...I chalked it up to one of the mysteries of life

Doc 1 06-24-2007 04:43 PM

RE: crankcase breather blowing oil
 
I like that Seaquester...:D

The oil in the tank gravity feeds into the engine to a ball check valve in the oil pump. When the engine is running the ball check will open with oil pressure and oil circulates through the motor, when you shut the engine down the ball check is SUPPOSED to stop the oil from entering the engine.....but.....a small piece of dirt or fiber could keep the ball offits seat and allow the oil to drain from the tank into the engine. If the bike sits more than a week or so the oil accumulates in the lower end of the motor and when you fire it up the oil pump is over whelmed and can't handle the volume of oil so it is pumped out the breather...as soon as it gets rid of all the excess oil it's good to go. I've seen two to three qt pump out very quickly. If you start your bike up ever day or so the pump can handle the small amount that drained into the lower end and pump it back with out you knowing a thing about the problem with the ball check in the pump. Its called WET SUMPING.

We still have WET SUMPING today in the Twin Cams but it's an internal oil pump and you cant see the leak inside....what we do see today with wet sumping is a huge power lose from the fly wheels running in all the oil.

Hope this helps clear upthat little lifes mystery.....:D

Seaquester5 06-24-2007 05:16 PM

RE: crankcase breather blowing oil
 
Doc1....You are the very best! That clears up that little mystery for sure, and good to know I was not too far out in left field thinking it was not a fatal issue huh? and by the way..we5t sumping can't be all bad!!!..Thanx again.

Doc 1 06-24-2007 06:05 PM

RE: crankcase breather blowing oil
 
Yes you did good thinking its no big deal....but you know it is repairable


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