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I pulled out the air filter on my bike to check it out and see if it needed replacing. As I pulled it out I noticed oil on the bottom of the filter. I looked inside the airbox (carburetored) and say a small pool of oil.

This can't be good? I rejetted the carbs about 2 years ago, but never put on the aftermarket exhaust. I know it runs rich because of that, but why would I see OIL in the airbox? Is this a gasket leak? Can't be good, I'm thinking.
 

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V-Twin Moddin
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I'm not sure about that, I think Larry will be the man for this. However, I've parted out a few bikes in the past and found the same thing in some of those. Of coarse the one with the most oil was a retired suzuki race bike.... :whistle:
 

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I wish I had an answer for ya, but I dont know for sure either..a gasket leak would sound logical to me though, since the oil would then be shooting out where the gasket seal should have been secure, and then shooting back up into the airbox...but yeah, I'll just chill till larry signs back on for this one :)
 

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Had the same problem on my Jeep. Was caused by a clogged PCV valve. On a motorcycle, it could be a clogged, pinched, or disconnected breather hose. Blow-by gases in the crankcase should be routed to the airbox for reburning. The crankcase is already pressurized by the pistons. The worse case scenario is excessive blow-by the rings which exceedes the normal pressure in the crankcase and sends an oil mist to the airbox.
 

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Some oil in the airbox is normal. Bikes don't use a PCV valve, they just have a hose direct from the crankcase to the airbox. As your bike's oil heats up and sloshes around it vaporizes. The mist is carried into the airbox where it condenses and coats the inside of the airbox, sometimes enough to puddle a little. Don't worry about it if you can wipe it up easily with a small rag.

Now, if your rings are shot, blow-by will will pressurize the crankcase even more and it forces the oil into the airbox in large quantities. You will know the difference if it happens, it will look like somebody poured oil into the airbox instead of the crankcase where it belongs.

HTH,
Larry
 

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And the legand has spoken. :bowdown:
 

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V-Twin Moddin
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Yes he has. Once he said something about the hose, I was like I remember that hose...found it on a few parts bikes.

Larry is the man! :dthumb:
 

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I feel like Im am now one, with the oil, the hose, and the airbox .. :bowdown: :bowdown:

Thanks larry, great stuff!!!! im sure Shan is breathing alittle easier bout now..
 

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larryg said:
Some oil in the airbox is normal. Bikes don't use a PCV valve, they just have a hose direct from the crankcase to the airbox. As your bike's oil heats up and sloshes around it vaporizes. The mist is carried into the airbox where it condenses and coats the inside of the airbox, sometimes enough to puddle a little. Don't worry about it if you can wipe it up easily with a small rag.

Now, if your rings are shot, blow-by will will pressurize the crankcase even more and it forces the oil into the airbox in large quantities. You will know the difference if it happens, it will look like somebody poured oil into the airbox instead of the crankcase where it belongs.

HTH,
Larry

Sometimes, at least in my experience, If my oil filter was really dirty or clogged, I experienced the oil mist and pool in my airbox, especially on my old cb 750 k4. I would change the filter and the problem went away
 
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