Oil in air box?

[webbcraft2150]

My 80G w/65 on it started running like crap so I started to check things out. I was suspecting a carb problem, but I decided tostart with the basics. Battery fully charged, plugs showed running a little rich. I pulled the stock air box to check out the air filter and I found oil in the "clean" side of the airbox. Needless to say, the filter was pretty dirty (Uni replacement). I cleaned the plugs and the air filter element. Its running alot better but I am curious where the oil came from. I had not overfilled the crankcase, change oil every 2 to 3 thousand miles (10-40 Castrol) and have not tipped the bike over in vears. It has been running in the high 90s here for the past two weeks but I dont hardass the bike when its this hot. Everything seemed fine on the ride in this morning, waiting to see what happens on the ride home, 95+_today.

[Madness]

webbcraft,

Was it motor oil, or could it have been filter oil? I know I have had mine actually drip out of the small filtered hole on the bottom of the box because I left too much oil on the filter. The filter holds very little filter oil. The rest will gradually run down and settle to the bottom. I now make sure the filter is well coated and squeeze all that I can out before installing. The extra oil didn't cause any poor running conditions for me, but it may at a certain point.

[Dennyz]

My XS has 80K+ on it and I found that if I fill to the middle of the sight glass I will get oil in my air box after high speed runs (70pmh+) on hot days. If I run my oil level somewhere bewteen the middle and low level mark, I get no oil in my air box.

I can imagine a couple of explanations for this, nothing concrete.

[strom]

AFAIK the standard has an oil vent hose runnin to the airbox.

LP

[fusionking]

My theory

Yup, and if the air filter is dirty and everything is sealed good it is like it is drawing harder on the vent hoses. (aren't they between the carbs and the element?) Also you know those pistons go backwards just as fast! Lotta air movin' in there. Also the hotter it is the more the oil expands etc.. Keep the filter clean and watch it very closely and let us know what happens! P.S. I don't run that hose and haven't forever.

[sixtysix]

Yep you can get a little oily crap in the air box, I got tired of cleaning my UNI so much, so I bought one of them cute little Hardly type filters and run the crank case vent through this now. The only downside is sometimes you smell oil at stop signs and stuff.

[Mike Hart]

I gotta get one of those. My current arrangement pukes on whatever is under/behind it.

[newmaac]

Gary, that looks great!
I too eliminated the breather hose to the airbox, but basically just have a fuel filter hidden under the tank that the crankcase breathes through.
The original intent was to change the filter element with each oil change, but it is hidden pretty well, so I never think about it.
My valve cover recently started leaking pretty badly. When I checked it out, I found that my homemade breather element was completely plugged.
My point being; by all means, get rid of the breather to airbox connection in order to keep the airfilter and carbs clean, But don't forget to check whatever crankcase filter element that you decide to use.
I will have to look into getting one like your "Hardly" breather. No sense hiding it when it has a nice appearance!!.

Mike