Milky white oil

08 yz450. Finally got everything back together, put the oil and coolant in it and she fired up first kick. I let it idle about two minutes shut it down and when I pulled the dipstick the oil looked to be a milky white color. Now there is a small hole in my rad that is going to get fixed up tomorrow but that's external. From my research on this it could be water or a head gasket. The motor has been open but just covered up with rags while I wasn't working on it so could it be the condensation that got in it and mixed with the oil. It's been awfully humid and rainy lately or should I be leaning more toward the head gasket? Any input would be appreciated. Thanks!

I think it's a head gasketImageUploadedByThumper Talk1428530749.142358.jpg

Did you remember to put orings around dowels when rebuilding it?

Which dowels do u mean? On the head?

The O-rings he's referring to don't exist on the '06 and later models.  His '04 had one fail.


Assuming no cracks or holes, there are three places where water can get into your oil:

  • The O-ring between the crankcase and the right crankcase cover, above and behind the water pump
  • The base gasket (no O-ring)
  • The head gasket

How did you torque the head?  Did you reuse either the head or base gasket?

I followed the manual on the torques but I reused both gaskets. I didn't split the cases only had the head and cylinder off. I just ordered a whole engine gasket set bc I figured it was the head gasket. So they ought to be here tomorrow or Saturday and I plan on changing both the base and head gasket. Hopefully that'll cure my problem and I got the hole in the rad fixed and pressure tested today so that's all good

I just didn't have the gaskets and never had to change one on all my two strokes unless there was a tear. Still got a lot to learn with these 450s!

Just was installing the new gaskets base, head, and stator pulled off the stator cover and found this oring laying in there anybody got an idea where it's from. This thing is really P***ing me off I just wanna ride already and it just seems like one thing after the nextImageUploadedByThumper Talk1429149583.602705.jpg

On the stator cover upper left by the oil fill there is a dowel and I am pretty sure there is an o ring around it. I would check there.

On the stator cover upper left by the oil fill there is a dowel and I am pretty sure there is an o ring around it.


There is.  There will be a recess cut around the bolt hole where the dowel is inserted to accept the O-ring.

Thanks much guys I'll take a look when I get home tonight

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