Blow By
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Road Master
Joined: Oct 2007
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From: Southern Indiana
Blow By
I'm getting an abnormal amount of blow by recently, checked the oil level tonight and see it's just a little over full. Could it be from this? Going to pull some out tomorrow to get it at the max lvl.
Road Warrior
Joined: Jul 2007
Posts: 1,707
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From: Newtown, PA
Combustion gases blowing by the piston rings (blow by) will pressurize the crankcase. Oil consumption is increased by excessive blow by - not decreased. All engines have some degree of blow by as the seal of the rings is not 100% to the cylinder walls. Excessive blow by is caused by worn cylinder walls, worn rings or both. The result will be decreased power and increased oil consumption.
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Road Master
Joined: Oct 2007
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From: Southern Indiana
That makes sense, however, if the engine is mistakingly over filled slightly will the crankcase pressure be higher and increase blow by? I'm asking because I don't know. I cleaned all excess off, rode around 60 miles and had oil that had blown back out enough to have evidence on the batt cover and pass pegs.
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Road Master
Joined: Oct 2007
Posts: 1,234
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From: Southern Indiana
I can wipe my hand under the air filter and it has oil on it after 60 miles. This seems excessive, but I could be wrong 
Road Warrior
Joined: May 2008
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From: ,,
Just a thought, Its cheaper and faster then tearing apart the heads/jugs.
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Road Master
Joined: Oct 2007
Posts: 1,234
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From: Southern Indiana
That looks like the V&H intake, I'm not sure how it mounts or how it feeds oil from the heads. I know the SE one shoots it back into the intake. You might want to check those seals or ports to make sure that they aren't leaking and giving a perception of blow by.
Just a thought, Its cheaper and faster then tearing apart the heads/jugs.
Just a thought, Its cheaper and faster then tearing apart the heads/jugs.
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Outstanding HDF Member
Joined: Jun 2007
Posts: 2,687
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From: Kalaui Kona HI
I just fill the oil just below the full mark never get blow by. If the oil is up to and above the full mark blow by. It only happens when the stealer does an oil change.
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From: S.E. MO
Yes if you have to much oil in it you will get more blow by. Mine was a little over full once and was steadily cleaning out the air box. When I serviced it the next time I didnt fill it as full and it went away.
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