breather tube mods

hi all. i have a 2004 yz450f i ride in all weather conditions,100 degree dust to 30 degree wet, i have noticed when i ride in the wet my oil filler cap will have a white spooge on the underside of it. if i pull the hose off of the valve cover i can see evidence of mud,water at the top of the pipe. if i ride in the dust i see evidence of dust at the top of the pipe.

i would like to modify this and after a through search of thumpertalk i see that several people have done mods but i cant find any pics.

has anyone done this mod? has it worked in the long run? any pics?

thanks in advance for all the quick replys. :bonk:

we offer tt member discounts! :applause:

Has anyone got some pics? I'm also interested to see how other have done this.....

you're referring to the breather tube coming out of the valve cover? why cant you just put a small filter on the end?

You could, but a foam filter won't stop water.

You can do two different things about this:

Put a T in the line that vents the tank to the cam box and run a line from the T down the steering tube next to the gas tank vent. That will eliminate the engine's ability to draw water up through the vent at low or cranking speeds, and a foam filter should stop sand and stuff like that.


Go to an auto parts store and look at the selection of the little air filters that are made to connect the PCV air vent hose on an automotive valve cover to the air filter. Find one with the right sized hose barb on it. Cut away the filter part, but leave a bit of a flat flange on the end of the barb. Cut a hole in the air boot in the flat area on the upper left, and push the barb out through the hole from the inside, gluing it in place. Then, rotate the breather 90 degrees on the cam cover so it runs back along the top tube and cut it short enough to fit. Your breather will now be located on the clean air side of the air filter. This may cause there to be a little breather oil blown into the intake, but there shouldn't be too much in most cases.

thanks Ill see if I can find one at the parts store.

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