leaking WR400

25 replies to this topic
  • storm 800

Posted July 09, 2005 - 05:22 PM


Help I just joined the ranks of the four strokes. I have a ? on the WR400 Mine seem to drip oil after riding from the tube that comes from the head! When its runing you can feel some blow by but no oil. ThAT COMES WHEN YOU PARK IT from the tube. Is this anywhere close to normal? Other than that I think I can get used to it over my two stroke.

  • Rich_in_Orlando

Posted July 09, 2005 - 08:37 PM


It's normal. Relax.

  • storm 800

Posted July 10, 2005 - 06:26 AM


So that normal? Having not been around four strokes I have to take your word for it! Seems kinda strange though! :)

  • byggd

Posted July 10, 2005 - 07:19 AM


My 03 wr450 never did but my 02 426 does. I've read a few threads and everyone says it's normal on 02 and older, as long as it's not a Harley sized spot :) Look at it this way....it's a easy way to tell if your oil needs changing :) This is one reason I haven't run the hose to the air cleaner, not sure I want the oil going there

  • bluebike1999

Posted July 12, 2005 - 02:03 AM


yeah it's ok. and it's ok to just about crap ya daks when you first see it.
mine actually had a very slight milky colour and to everything i've learnt about 4 strokes, this is a problem. I did the same thing, ran in here and asked on tt. problem solved, no problem

  • Conan_'dale

Posted July 12, 2005 - 06:53 AM


Storm 800.

It's normal. My 2000 WR400 does the same thing. I ran my crank breather hose to my airbox and problem solved. :applause:

  • storm 800

Posted July 12, 2005 - 02:05 PM


Ok I wont worry about it then ! Other than that I am starting to really no REALLY like the fourstroke! I even figured out how to start it on the first or second kick! Thanks for all the feed back

  • Yamaha WR400F

Posted July 13, 2005 - 07:22 AM


Not only does it leak oil, but I'm sure if you look on this forum, You'll find it also sucks up water, when your stream crossing.
I also did not like the idea of running the hose up to the airbox.
Oil running in the air box, not a good idea to me.
I work at a Construction Dealer Co.
I found a discharge hose larger diameter than hose on bike.
I cut the original hose so it just made it to the clamp, slipped this one over, even has a end plug with attachment, so you can quickly drain the oil from the hose.
No more stalls crossing water.
Once I take a pick. I'll post it.

  • WRider995

Posted July 13, 2005 - 10:04 AM


Storm 800.

It's normal. My 2000 WR400 does the same thing. I ran my crank breather hose to my airbox and problem solved. :applause:

I left mine at the stock location since I'm not a big fan of water crossings. It's normal for it to drip a bit after each ride. Enjoy!

  • byggd

Posted July 13, 2005 - 11:42 AM


No more stalls crossing water.Once I take a pick. I'll post it.

Cool idea :applause: I'll look for you to post the pic

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  • storm 800

Posted July 13, 2005 - 02:03 PM


You closed off the hose ? I thought it was the crankcase breather tube! I didnt relize you could block that off! I like the idea though. Musta made a plug like the one on the airbox. Cant wait to see.

  • tp3dxf

Posted July 13, 2005 - 10:31 PM


I pinched the same hose between my skidplate and frame once after a oil change. I didn't notice it at the time. But after about a hour or so of riding I noticed I had all kinds of oil blowing out of the top of the head. So much pressure had built up that it actually blew out the rubber gasket on the valve cover of the bike.

As I tried to push the rubber gasket back in to the head I noticed that my breather tube was pinched off between my skidplate and frame. This is why I blew out the rubber head gasket.

I removed the pinched off breather and was able to slip the rubber gasket back into place on the head. It has been fine ever since.

Never completely block off the breather tube.

  • Yamaha WR400F

Posted July 14, 2005 - 05:53 AM


I did not block off the tube, dont do that as stated you'll blow out the head gasket.
I cut the hose shorter, slipped this LONGER hose over it, which has a removeable plug in it.I just took the top off it.
Very fast fix, only took a couple of minutes.
We sell the hose here complete for $5.37

  • byggd

Posted July 14, 2005 - 08:12 AM


What keeps the larger hose from blowing/falling off? Do you have a pic? :applause:

  • Conan_'dale

Posted July 14, 2005 - 10:37 AM


Please post a picture if you can... It's difficult to understand what you are talking about. Thanks!

  • Yamaha WR400F

Posted July 14, 2005 - 11:19 AM


I know.
I have to get a picture hosting site first. :applause:
Wash the bike.
Change the front wheel bearings.
Never a dull moment.

  • byggd

Posted July 14, 2005 - 11:38 AM


I have to get a picture hosting site first.

Use this site, it's free :applause:


  • Yamaha WR400F

Posted July 15, 2005 - 07:04 AM


I washed the bike.
Replaced the front bearings.
Took the pictures.
Now I can't find the cammera port plug to download the pictures to the computer!!

I was talking to one of our Mechanics, who used to ride semi-pro.
What he sugested was to put a one way check valve in the end of the hose.
That way your sure nothing will get back in.

Anyone's thoughts on this?

  • byggd

Posted July 15, 2005 - 10:36 AM


I was talking to one of our Mechanics, who used to ride semi-pro. What he sugested was to put a one way check valve in the end of the hose.

Not sure on that one. Mine only seems to blow air out so I'm not sure when it would pull air in, might only be when you are starting it :applause: Question is does it "need" to pull air in. Guess you could try it and see in the hose calapses.

  • Yamaha WR400F

Posted July 15, 2005 - 03:20 PM


I finally downloaded pics.

1.Shown with hose pulled out, end plug out.
Posted Image

2.Shown hose in place cap on.
Posted Image

3.Further shot.
Posted Image

4.A pic of a new hose assy. uncut. ( I cut the top part off )
Posted Image

5. A pic of my thumb engaged air release valve system for the front shocks
Posted Image


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