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GuyGraham

Milky oil residue in the crankcase breather pipes - '08 450

6 posts in this topic

I discovered milky oil residue in my crankcase breather pipe (the one from the starter housing up to the 'Y' piece

I cleaned it out, but after the next ride it was back

Stripped off all the hoses and cleaned them again, also took off cam cover but no sign of it in there

It is also in the starter clutch housing which I have cleaned out

Changed the oil, but the oil is not contaminated

Just read in another thread that it could be air mixed in with the oil residue giving the appearance of milky oil.

Pulling the pipe off with the engine running there sure is a a lot of air movement in those pipes

Don't know where the water could be coming from

I haven't done any water crossings

I haven't washed the bike recently (been using it on the street)

I am not losing any coolant

Anybody else finding this - very easy to check, just pull the pipe of the starter clutch housing and you will see it in the rubber pipe if you have it

Sure would be comforting to know if this is normal

On a side note - why is the hose routed into the bottom of the air box

Surely this would allow dusty / dirty air to be sucked into the pipes and ultimately into the engine oil, or even worse water, if the airbox had a bit of water in the bottom of it

I was think of routing it into the now redundant AIS outlet which is after the air filter, on top of the intake boot - good or bad idea?

Any help appreciated

Edited by GuyGraham

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Possibly condensation usually from starting and stopping the engine without it reaching full operating temperature.

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Uhmm I got the same thing on my and everything looks good on the bike so condesation sounds right I guess

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Possibly condensation usually from starting and stopping the engine without it reaching full operating temperature.

Yeah thats what I thought, but I've been trashing it for a good hour at a time before re-checking, yet its still there

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On a side note - why is the hose routed into the bottom of the air box

Surely this would allow dusty / dirty air to be sucked into the pipes and ultimately into the engine oil, or even worse water, if the airbox had a bit of water in the bottom of it

I was think of routing it into the now redundant AIS outlet which is after the air filter, on top of the intake boot - good or bad idea?

Any help appreciated

I have mine routed somewhat like a YZ. Using some different tubing, after the joint of the two pipes I have mine go up in front of the left radiator and then capped with a small uni filter. I also did not like the idea of an open pipe on the dusty side of the airbox, but the way the original was running downhill, it could also take oil blown out of the valve cover and have it run into the airbox instead of back into the bike, even with the tube in place that runs back to the starter. You could route it to the AIS fitting on the clean side of the air filter, but probably not a great idea as these bike do blow oil and if put there it's going straight into the carb. If routed up, you will not lose oil either.

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