426 leaking out the head breather hose? why?

8 replies to this topic
  • skibum_1260

Posted July 10, 2008 - 09:51 AM


I had no oil leaks on my 01 wr426 then i was reading my manual one day and it says that when checking the oil your not suppose to screw it into the frame you just drop it in and read it with the bike level, well i always screwed it in, ever sence ive filled it up to the line this way its been leaking out of the valve cover breather hose, pretty consistant drips to, am i wrong is it just to full or is there another problem>

  • GCannon

Posted July 10, 2008 - 10:09 AM


A few drops found when you stop after riding are normal.

  • matt4x4

Posted July 10, 2008 - 10:48 AM


your oil gets "vaporized" in the head (tiny drops mixed in the air) - they will travel into the breather hose, deposit on the walls and run down and drip out the bottom, if you weren't moving they would fall to the ground, but on a moving bike the air flowing past the hose outlet picks them up and splatters them onto your frame.

  • skibum_1260

Posted July 10, 2008 - 11:04 AM


theres more then a few drops, theres a descent little puddle under the bike after an hour or two of sittin(still drips out of the head breather), my left boot is also covered after ridin( i have the hose sticking out so i could be sure thats where it was coing from) my last 426 wouldnt leak a drop, am i right on how i check the oil or should i go back to screwing the dipstick in?

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • matt4x4

Posted July 10, 2008 - 11:22 AM


Next oil change, put in 1.5 L if you're only changing oil, 1.6 L if also changing the filter, THEN measure your dipstick after running it 2 minutes and letting it sit for 1 and that should get you your mark for future readings. If you are NOT doing this particular checking procedure - chances are it's overfilled. (measure with bike perfectly upright, not on kickstand)

I measure my 400 with it UNSCREWED and it's up at the top of the knurl mark, maybe this particular bike you have has a stronger oil pump compared to the last bike.....
Check the breather hose all along it's length for any pinched spots - if it is partially pinched but still allowing air past, this will actually speed up the airflow in the hose, possibly spitting the oil more than normal.

  • skibum_1260

Posted July 11, 2008 - 11:28 AM


i changed the oil and put in the recommeded 1.6 liters and just a few drops when i first rode it and now none, i think shes good! thanks again.

  • WildRide

Posted July 11, 2008 - 03:37 PM


Totally normal. The oil mist condenses in the tube and drains out after sitting.

  • maxtherat

Posted July 12, 2008 - 04:15 PM


I put a barbed pvc 90 deg fitting on the end of my vent hose and now it shoots any oil straight down. It just rests on the edge on the skid plate and it stays in place.

  • muzzym

Posted August 03, 2008 - 10:38 AM


I have an 02. Just noticed oil dripping out of the head vent tube as well. Is it normal to for these to blow air out of the tube while running? I think I have an engine issue aven though it seems to run ok. I am wondering if I broke an oil ring or have a head gasket issue? Any help is appreciated.



Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.