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Author Topic: Breather blow back  (Read 251 times)

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Breather blow back
« on: November 13, 2023, 09:53:01 AM »

OK first I hope I have this in the correct place.

Just recently I replaced the elite breather on my 2021 SESG with a new screamin eagle extreme breather. I love the look. Feels like it's got a tad more giddy up but that's probably in my head.

So rode bike around 1000 miles when just recently see oil on right saddle bag and rear head pipe. Not alot but easy to see on my white bike. Found oil on the inside of mounting plate. I took off the 90° turn and tightened up breather bolts. The left breather bolt was not tight.

I have to ride some to see if that fixed the problem.

The stock elite breather didn't blow out any oil at all. Any ideas as to why this extreme breather is blowing oil? Thanks

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Re: Breather blow back
« Reply #1 on: November 15, 2023, 06:01:07 AM »

There is always going to be blow-by. Think of the breathers like the PCV valve (positive crankcase ventilation) on a car. The breather bolts handle all the pressure in the crankcase. With 121 cubic inches there will always be pressure in the crank case from blow-by past the rings plus additional pressure from the oil pump trying to scavenge oil back to the oil tank.
Make sure you are not overfilling the engine oil tank which will only make it worse. If you travel a lot on highway (fast, high rpm’s) it will be more noticeable.
Some people will modify the air cleaner assembly and install an external breather to prevent oil getting burned with the air and fuel mixture. If you think it is excessive check your spark plugs and/or your oil consumption rate. If you're constantly adding a lot of oil between oil changes you might have a problem.
Excuses are the conditions under which you have failed.

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