milky oil in airbox

powdershred

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I have had a considerable amount of milky oil in my airbox and dripping out of the vent hole in the bottom of the air box also the drain line was full when I pulled the plug on it . It is coming from the engine breather line out of the crankcase ,what is this from .This 450 4 stroke is a snowbike
 

Lund

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I have had a considerable amount of milky oil in my airbox and dripping out of the vent hole in the bottom of the air box also the drain line was full when I pulled the plug on it . It is coming from the engine breather line out of the crankcase ,what is this from .This 450 4 stroke is a snowbike

ALL motor create condensation, that is your milky oil, its a normal thing that happens when you warm up and cool down a motor. Especially in cold temperature it will be a lot more noticeable.
It is completely normal.
In your case and like most all motors, the case breather (motor block breather) is connected to the air box via a hose. The motor when it is running creates condensation vapors that run up the case breather hose into your air box.
You need to keep the case breather clean and clear, so it means you need to maintain that system or you will eventually run into trouble. In warm weather, especially summer time the motor will not create nearly as much condensation and what it does will be reburned into the combustion via air intake.

Also as a side note, crank case condensation is amplified as the motor rings wear, eventually a worn motor will get blowby (gasses from the combustion going by the rings) this on its own will also create a lot of condensation, as combustion gasses are a lot hotter then crank case base temperature's. The cooling effect creates the condensation in this case.
 
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NoBrakes!

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I have seen guys put a crankcase vent K&N filter on snow bikes
 

powdershred

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its carberated so it didn't run long on its side but these things are heavy enough to pick up when they are on there side lol
I'm sure that didn't help ,it makes a fn mess on the garage floor when it defrosts
 

powdershred

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have thermostat ...bike runs at 135f which is definitely on the cool side working on a engine blanket now to get temps up
it seems to run fine just lots of condensate . What would a reasonable operating tempeture be on a 450 4t
 
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