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Crank Seal Help??

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my trans oil on my o3 rm250 is coming out like light grey milky stuff and ive also heard that that can lead to my bikes smoking and spooge problems,can someone please walk me thru changing my crankseal/seals as far as what i need to remove the book shows it with engine removed already.i have the top end of now and do i have to change both?or just the right side...please lmk any helpfull advice thanks to everyone ,patcap.

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I don't think crank seals are what you need for that. Sounds like you are getting water in your oil, you will need to replace your water pump seal.

Ihave not look at the newer models but on my old bike(1996) you had to splilt the cases to change the water pump seal.

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I don't think crank seals are what you need for that. Sounds like you are getting water in your oil, you will need to replace your water pump seal.

Ihave not look at the newer models but on my old bike(1996) you had to splilt the cases to change the water pump seal.

yeah im not sure if i have to split em or not ive heard both ways appreciate the help,patcap

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I don't think crank seals are what you need for that. Sounds like you are getting water in your oil, you will need to replace your water pump seal.

Ihave not look at the newer models but on my old bike(1996) you had to splilt the cases to change the water pump seal.

on my 03 rm 125 you dont have to split the cases to change the water pump seal all you do is pull the right cover i think and its in there

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on my 03 rm 125 you dont have to split the cases to change the water pump seal all you do is pull the right cover i think and its in there

thanks man i figured you didnt,how do you like the 03rm i personally love my bike its kinda moody at times but its a very well thought out bike,anyway take care.

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Yesterday when I drained my oil it was also milky. Is there any other signs if your water pump seal is gone? I always thought that water runs out the little hole on the pump and surely the water level in the radiator will have dropped? Mine has neither of those signs...

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Have you checked that the breather hose on top of the barrel was in place corectly. If it's not on , when you wash the bike water can run down the angle fitting into the crankcase.For the oil to be milky , water has to be getting into the clutch area. It has to come from the bikes cooling system or it's getting in externally. Thats why I though I'd tell you about the fitting. That happened on my son's RM 125.

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Thanks I will check out my breather hose.. makes sense. Just weird that the coolant level has not dropped! But the oil looked almost like milk!! I replaced oil today and riding tomorrow so will check it out again. Thanks.

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My motor is all new on the inside (seals, crank, piston, other stuff) and my trans oil always comes out a dark grey. My coolant is dark green like it always was. Do I have a problem. Also the oil is still thick when it comes out.

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as long as the oil isnt contaminated with gas. you're not losing oil or gas and there is strong compression then you're in good shape.

usually if your rings are bad and u have blowby the compression is lost in the bottom end and it pops out the seals.. when i installed a piston that wasn't fitting the bore it ended up popping out the right hand side's crankseal and gas contaminated my oil.. came out greyish and not as thick. so my fix was a oversize piston (.02") and new crankseals.

my advice would to get a compression tester and run a simple test. get a reading with it dry (no oil added into the cylinder) and then take a wet test. a wet test is when u squirt a bit of oil around the sides of the piston and it helps create a better seal. run a new test, if you end up with a significant increase in compression then a new top end is in order. if you need advice on a rebuild, ask.

changing the crankseals are easy and just requires a good ratchet set and basic mechanical knowledge. pull off the engine cover, remove the bolt holding the first gear on. i pull out seals using a wood screw, i screw it into the seal and pull it. apply blue loctite to the edges of the seal and put it into place. i also like to peen the area the seal sits in with a nail. just put a few burrs on the edges so it grabs better.

hopefully this will answer everybody's questions. good luck

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Hello Alex,

When you say always grey. Then I would say no. Most gearbox oils will come out grey. Metal and other clutch debris contaminates the oil. You will know when you have coolant in your oil. It's very milky looking and comes out thick. It also makes the clutch very grabby. As it thickens the oil. To remove the water from the crankcase it will take several flushes. I use ATF Dexron 3 in my son's 02 RM 250 crancase. I change it frequently.

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