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IronButt
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386 Posts
Discussion Starter #1
Arlen Ness web-site reads that the Big Sucker eliminates blow by. I see that the kit comes with banjo bolts with o-rings for the breathers. Are these breather bolts acting like plugs?
 

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In disguise
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2,727 Posts
The breather bolts are hollow, allowing any oil mist that comes out of the heads to travel through them and through the ports in the Big Sucker body, exiting near the intake port. The O-rings are there to contain the oil to these passages and not get on the outside of the heads or Big Sucker housing.
 

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IronButt
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386 Posts
Discussion Starter #3
Thanks,
after I posted I found some info on the ports. So if you have blow by it will just get sucked into the intake as does my K&N breathers.
 

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The Anti-RUB
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1,901 Posts
the SE A/C does the same thing.
 

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IronButt
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386 Posts
Discussion Starter #5
When I replaced my heads, I noticed a lot of oil in the intake and a build up on the top of the pistons. I had oil blow-by since the day I got my 07.

The weird thing is after I installed my new heads I haven't seen as much blow -by. Does that make any sense? I guess if it reoccurs I will have to run a drip line agian.
 

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In disguise
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2,727 Posts
The Big Sucker is only capable of handling an incidental amount of oil in the breather. I have an Evo and I have experienced oil in the breather even after installing it. Between the Big Sucker, and the old-time fix of enlarging the oil return holes in the middle rocker box plate, and installing a "The Cure Vent Plus" ball valve in the other rocker box plate hole, I have finally pretty much fixed the problem.

On TC motors, I hear that the Doherty Machine Myst Free device in the rocker boxes generally does good things to fix the problem. You may have to go that route to completely eliminate the issue. Don't know what new heads you iinstalled, but they may be better at allowing excess oil to return to the crankcase.
 

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IronButt
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386 Posts
Discussion Starter #7
They were cnc/ported by Hillside Cycle. I hope the breathers continue not to have heavy blow-by and I guess only time will tell.
 
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