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How is water getting in my case?

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I have an 01 CR250 and everytime I do a creek crossing, large or small, I end up with water in my case when I drain the oil. The case breather vent is the only way, right???? It doesn't leak oil anywhere, but I always find water in my oil when I drain it. If it's coming in through the case breather, what can is do?

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I have an 01 CR250 and everytime I do a creek crossing, large or small, I end up with water in my case when I drain the oil. The case breather vent is the only way, right???? It doesn't leak oil anywhere, but I always find water in my oil when I drain it. If it's coming in through the case breather, what can is do?

Although water is not great, its the dirt that comes with it that will do damage to bearings and gears, etc. Are you sure it isn't happening all the time and you only change the oil after water crossings?? If so then i'd check the water pump shaft seals. If not...

Its strange that it only happens through water crossings (well it is and it isn't). You should be able to get through pretty deep water without taking water in through the breather tube... i'd check other things like countershaft seal and kickstart seal, etc... and maybe even think about doing a pressure test... one possibility (and i could be jumping to conclusions) is that you might have a slight crank seal leak which is causing a slight vacuum in your transmission case each piston cycle and is sucking in water when you submerge the breather tube. Just a thought. Read the sticky at the top of the Honda 2 stroke section on building a pressure tester.

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If you're getting water in the cases, replace the crankcase side cover gasket. The water pump outlet passage to the cylinder goes through the right side cover into the crankcases. It is possible for water to leak through this joint and I have seen it happen once on a 2001 CR 250.

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If you're getting water in the cases, replace the crankcase side cover gasket. The water pump outlet passage to the cylinder goes through the right side cover into the crankcases. It is possible for water to leak through this joint and I have seen it happen once on a 2001 CR 250.

Good point!

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Thanks guys. I drain the oil after every ride, because every ride I do involves some kind of creek crossing or five. maybe I should start by doing a ride without any water crossings, then drain the oil to see if there is water in there. Then at least I'll know if it's coming from the creeks or my cooling system.

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If you're getting water in the cases, replace the crankcase side cover gasket. The water pump outlet passage to the cylinder goes through the right side cover into the crankcases. It is possible for water to leak through this joint and I have seen it happen once on a 2001 CR 250.

But if water is getting that way, then shouldn't oil be leaking out that way? My bike doesn't leak oil at all.

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Nope. Water is under pressure, oil is not. Flow always follows the pressure gradient. Even when the bike is not running, there is a head pressure from the radiators that will push water into the crankcase. It's a $10-15 part at your local stealership, that's not much more than the cost of an oil change. Just throw it in and see if it fixes your problem. Make sure the weep hole for your water pump isn't plugged. You could be getting water through the water pump seal, usually you'll see water leak out from under the water pump if this is the case. If the weep hole is clear, I would really lean towards a bad side cover gasket.

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