What happened to the engine oil?

[Rapidrob]

I've not been able to ride my mini bikes for two seasons due to surgery on my right hand.
I dug out my CHI-COM mini with the Predator 8HP engine and let it warm up for a few minutes.
I stored the mini with all gasoline removed and fresh motor oil in the crankcase. The mini is stored in my garage which is as dry as a pop-corn fart.
When the oil was drained, it came out a yellow color. The oil is still normal in lubrication and smells normal. I've never seen this before.
I live in the desert. It is NOT water in the oil. I've seen and smelled water in oil many times in my life. Any ideas?

 

[Skipp]

Water from condensation….the warm up and shut down is murder…

 

[Harquebus]

Isn't oil mildly hygroscopic in its own right? it's just a slow absorber

 

[f4radar]

Maybe water got some place it wasn't suppose to when it was getting washed.

 

[Harquebus]

Noticed similar on one of my first cars, a hand-me-down 1980 Honda Civic. The oil filler cap on the valve cover always developed a layer of oil on the underside that was the color of coffee with creamer. It always bothered me because it didn't look right. Never noticed it in the crankcase oil however.

I read years later it may have indicated a slightly blown head gasket that allowed coolant to weep into the crankcase but burned off most of it. What remained collected on the oil cap.

 

[sparkwizard]

Plugged PCV system would cause that on your Civic.
I have never seen oil in a small engine get milky like this unless it ran with water in the oil.

 

[Rapidrob]

PVC is clear. None of the other mini bikes engines have this color oil, same oil used.
All have the same type and model of engine.
The last time the engine was run was August.
I poured the oil into a lab glass beaker heated the oil up. No steam and no separation of water under oil when cooled.
Strange.