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Reasons for oil comming out of oil breather hose?

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Hey guys. I'm talkin about the engine oil breather hose on my 01 YZ250F (The hose that comes right alongside the left side frame rail)

About a month or 2 ago, I lost the timing plug/screw on the left crankcase cover. I put a new one on from the dealer when I got home in about 5 days. Changed the oil and no dirt came out, and my filter stoppe everything.

But ever since then, the hose has breathed out more than it has in the past. Before the incident, there would be no oil that would come out, if any. Now every time I go riding, the frame rail under the hose and all the way to the peg is covered in dirt, and under the dirt is oil.

Is there anything that could cause this problem? The oil level is usually between the add and full marks, and if it is higher than the full mark, it's by about .5 a centimeter.

-Phill

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too much oil, too high of engine temp, cheap oil, a broken compression ring are some things that can cause it. It could also be nothing more than coincidence that the oil in the tube finally migrated to the exit at the same time you started fretting over it.

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My take on this is you've got blowby in your top end. That is what that tube is for is to vent the crankcase gases that have escaped past your compression rings. Start your bike and put your hand under the tube. There will always be some, but if you're feeling major pulses of air then you've got excessive blowby and need new piston/rings.

How many hours on these rings/piston?

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