YZ250R Grease in Oil

I have an '03 YZ250R; while doing routine maintenance, I was changing oil and I noticed a few globs of lithium type grease globs in the bottom of the pan. What is this a sign of?

Someone using grease in the bottom end instead of ass'y lube?

Last time the botom end was done it was done @ Pro Circuit; never saw grease during oil change b4. I will assume that PC knows what they are doing.

water in the oil?

Yeah, a buddy of mine suggested that. Where could that come from? Can the radiator leak into tranny? Is that something that goes away or do i need to put in an add mix of some sorts?

Water pump seal.

Water pump seal.

That seems reasonable, is that a big ordeal to do or is it simply drain the coolant, stick new seal and gasket on and refill?

If it is engine coolant, it's extremely unlikely to have come through the water pump shaft, as there are two seals on the shaft, one for coolant, one for oil, with an air gap vented to the outside below the water pump housing. The gap exists for the specific purpose of preventing oil and water from cross mixing in either direction at that point, and if the coolant seal fails, coolant will run out the escape port rather than into the engine. (See the drawing)

If it is engine coolant, the more probable source is the cylinder base gasket or the right crankcase cover gasket at the water passage from the pump to the crankcase.

In most cases, a coolant leak would also cause there to be a small amount of water/coolant in separate liquid form in with the oil. Look for it in the first few ounces of fluid that come out of the drain plug. Otherwise, it could be environmental water you picked up crossing a creek or washing your bike, or even condensation from the air.


Thanks for the input Gray, I will keep my eyes on this and drain a bit o' oil out of the drain screw and inspect.

On exception, not the rule, I will wash at the track and load up for the ride home. By general rule I start and occasionally "putt" down the street to "air out" when it's washed...

After you wash the bike do you start it and let it warm up. That will drive any water out from washing the bike. Things like the flywheel rusting are sure signs of washing and then not starting the bike to get the moisture out

You need to keep in mind that this ia a two-stroke. It would take a considerable amount of time to warm the gearbox oil up to 150 degrees so that captive water could evaporate. Even in a four-stroke, getting the oil that hot takes longer than you think it does.

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