Milky oil

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#1
I have milky oil in my 2002 YZ250 which I recently purchased. The coolant is a little low, just to the top of the tubes inside. I'm thinking it is the waterpump seal.

My questions are could it be something else, like the headgasket or is that not possible - I'm new to 2 strokes/dirtbikes so I'm not sure.

Also can I replace the 2 seals without pulling the case off? The manuals show one on each side so I think I need to pull the crank case off? I just want to make sure and not do extra work.
 
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#3
sixds said:
you just have coolant in your oil.
Thanks tips, I thought that was pretty obvious which is why I'm asking the likely causes aka waterpump seal or headgasket.
 
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#7
ya lol, how milky was it? ive got a little milk in mine but i dont have the time to fix it.
 

IndyMX

Crash Test Dummy
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#8
Mazstyle said:
I have milky oil in my 2002 YZ250 which I recently purchased. The coolant is a little low, just to the top of the tubes inside. I'm thinking it is the waterpump seal.

My questions are could it be something else, like the headgasket or is that not possible - I'm new to 2 strokes/dirtbikes so I'm not sure.

Also can I replace the 2 seals without pulling the case off? The manuals show one on each side so I think I need to pull the crank case off? I just want to make sure and not do extra work.

It's not the head gaskets.. It's most likely your water pump seals..

You shouldn't even have to pull the head.. Don't bother with that, unless you know there's a problem in the topend.

Just do the the water pump seals...

I don't think you need to split the cases to do it, just take off the right side cover. I could be wrong though.
 
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#9
84cr125 said:
ya lol, how milky was it? ive got a little milk in mine but i dont have the time to fix it.

It was grey the first oil change, which who knows how long it's been since the last.

I did 2 more oil changes this afternoon and it was a little milky after each....
 
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#10
If the water pump seals were out, it would be leaking water out the tell-tale hole underneath the waterpump housing. Head gaskets wont put water into the transmission.

By milky, is the oil gray or is it kind of milk and coffee colored? Gray oil is normal for MX bikes, it's debris from the aluminum clutch plates. A tan color of mily is from water emulsified in the oil.
 
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#12
How much pressure washing do you do? Some bikes (90's up Hondas in particular) have water passages in the crankcase. A bad right side cover gasket could allow water to leak into the transmission.
 
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#13
my bike does the same thing. its a 95 rm 250. i used to have this problem on my 78 rm 250 when i was a kid. i thought it was from gas, but the crankcase and trans are seperate so.... . im gonna buy gaskets to do the top end soon so ill replace the pump seals also and report back with results. also i seem to always be low on coolant and i can smell antifreeze after riding.
 
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#14
76GMC1500 said:
If the water pump seals were out, it would be leaking water out the tell-tale hole underneath the waterpump housing. Head gaskets wont put water into the transmission.

By milky, is the oil gray or is it kind of milk and coffee colored? Gray oil is normal for MX bikes, it's debris from the aluminum clutch plates. A tan color of mily is from water emulsified in the oil.

It's more of a greyish, I've changed the oil twice now I'll ride it for a bit keeping an eye on the coolant and see what happens. I don't ride through any water and the bike is pretty new, I've never washed it yet I've only rode it twice...
 
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#15
Sounds like your first MX bike. We get a lot of complaints about gray/milky oil here, they're all from first timers. It's standard clutch debris. The only way around it is to switch out your clutch plates for steel ones. Otherwise, it's expected/normal to have aluminum particles suspended in the oil, making it appear gray.

Unclefiesta, check under your water pump for a hole. If there is no coolant coming out of this hole, you do not need to replace your water pump seals. However, if your bike is loosing coolant, it's likely you have a blown head gasket. Do investigate this as soon as possible because steam/combustion gas leaks through a blow head gasket can cut the surface of the cylinder/cylinder head. Once you get this kind of steam tracing, repairs start getting more expensive.