YZ power valve vent

[CHR!S]

Hello all,
I have a question about my '03 yz250. Exhaust is coming out of the power valve vent, and theres a thick, white-grayish liquid dripping from it too. What i would like to know is if this is normal. I just noticed this, im not sure if its been happening for a long time or not, i havent really looked.

Anyway, today i was changing my leaky exhaust gaskets, and looked at the powervalve and noticed that it wasnt protuding into the exhaust port. (im pretty sure, its the metal 'blade' at the top of the exaust port?), is that its normal position when the bike is off?
well, as usual any help is appreciated. thanks

 

[Pete Payne]

sounds like it is stuck in the open position .

 

[Someone]

With my 05 YZ 250, right after I start it (cold start), I get exhaust out of this drain tube. After I am done riding for the day, I usually get about 10 drops of some guey nasty black stuff that drips out of this tube. My 01 YZ 250 did the same thing. I never attributed it to anything abnormal.

 

[macdaddyk321]

My sons RM 125 is doing that too.
Checked into it and found a blown head gasket and power valve stuck open. Look in your crank case and see if there's the white grayish stuff in there too, if so you may have the same problem as us.

 

[CHR!S]

are there any simple checks i can do before ripping the whole engine apart? does this even sound like a problem to anyone?

 

[KX250Dad]

Spooge (black oil) out the power valve is a fact of life. In the old days the oil would simply carbon... new synthetics have all but done away with carbon issues thus more spooge. Grayish... I would suspect water from the head or cylinder base area. Check your coolant level... this would most likely point you as to the next direction. Black is good... greyish is bad. If you have developed a coolant leak you best find it and get it fixed quickly. As coolant enters the piston area it will phase change e.g., flash to a vapor then implode (back to liquid) and as this ocurrs it will remove metal from the cylinder ID and head making sealing virtually impossible. Pop your head and take a look A REAL CLOSE LOOK... should pitting be evident the next step would be to have the cylinder work done. That having been said I've had success using plastic/metal product to fill the crevices then dremmil sand smooth... thus far all has been working well... Do not attempt this should erosion/pitting entered into the dynamic piston ring portion of the cylinder.

Also, pull the power valve cover right side and make sure your linkage arm isn't broken. This is a spring loaded assembly at rest. To check operation gently rotate the bolt at the cylinder to emmulate the centrifugal force when increasing rpm... look into the cylinder and you will see your pv shoes move away from the cylinder. At rest they will be close to the cylinder wall however at no time will they or should they enter thru the bridge... if so the piston ring will snag and you know the rest of the story.