Constant oil leakage, is this common???

25 replies to this topic
  • steve lemley

Posted January 17, 2006 - 11:08 AM


My 99 WR 400 had always leaked a little bit of oil out the large hose connected to the very top of the valve cover (the one that runs down to the bottom for breathing and venting purposes I suspose). My oil level is always kept at full and apon oil chaanges I always drain both areas and filter along with adding exactly 1.7 quarts of yamalube 10 x 50 oil. Is this a common problem. I have to top up after every full day ride. I My buddy just baught the same bike and did an oil change. After returning from a 60 mile dual sport ride I noticed a oil smell and looked down to see his skid plate with a large amount of oil all over it coming from the same hose as mine does. This kind of leads me to believe that this is a common problem. Any ideas. Weld a screen to the under side of the valve cover, run thicker oil, etc. Help??????????????????

Anyone else having the same problem.


Posted January 17, 2006 - 11:36 AM


It's normal. The hose is the crankcase vent.

  • steve lemley

Posted January 17, 2006 - 12:18 PM


anyway to slow the spilage down a bit? I know in v-8's you can weld a screen to the under side of there the tube leads out of the vaqlve cover to slow the spillage. Has anyone ever done the same thing??? Any remedy???

  • byggd

Posted January 17, 2006 - 02:59 PM


A small amount is normal, say several drips after riding. But if it's a lot your rings may be getting old causing blow-by. Try to reposition the hose so it drips on the ground. This way you can see just how much you are losing and it will keep it off of your skid plate.

  • TallBoysWRF

Posted January 17, 2006 - 03:19 PM


My 99 does the same thing. I just cut a hole in my skid plate and most of the oil does go through it, I think. I still get oil build up on my plate because the oil gets blown around by the wind. Another option is to run the vent hose up behind the the number plate. I know guys that cross lots of deep water do this because if you stall your bike inthe water and the hose is below the waterline you will suck water into the engine. If you run the hose up behind the numberplate and put a filter on the end (Keep crap from going down the hose) I would think it would solve the problem since the oil would have to go all the way up, and not just over the hump before the hose goes down. Hope this helps. :thumbsup:

  • steve lemley

Posted January 17, 2006 - 04:13 PM


ill give it a shot and report back...If it works, it sounds like an easy fix to a messy problem and should be added to the free WR mods catagory. Thanks

  • dreadrock

Posted January 17, 2006 - 04:30 PM


yea i have my breather hose running to my air box. i have a 04 wr 450 and dont feel like pushing that thing out of the woods with a dead motor.i know on the 04s you just turn the hose around to face the airbox . take your airbox off your bike and make a hole down in the corner of your airbox.go buy a cunector and a small bit of hose for the inside of the airbox once you have it together seal it up :thumbsup:

04 WR450
04 crf150

  • bluebike1999

Posted January 17, 2006 - 09:00 PM


another easy one, and it's alright to just about shit when you see it.
normal on both counts.
possibly harder to find someone not having the same effect.
enjoy the 400 and its parking marker. (oil patch)

  • steve lemley

Posted January 18, 2006 - 07:31 AM


Once again thanks. It just worried me a little cause by buddys 400 had quite a bit on the skid plate the day we rode 60 miles 40% road 60% dirt. We both have plates on the bikes and do probley 25% of our riding on the streets. At a constant 5th gear in the "revs" a little, his spits a good amount of oil. Good to know there is a easy fix... Im an old chevy street racer and we used to say if it wasent leaking its probley going to blow up.. I guess the same pretains :thumbsup:)) Anyway, im loving my bike. Its true what the die hard yama guys say (im turning into one), you cant get it any better than these bikes. Ive done all the free mods and holy hell what a difference. !!!!!!!!!!!!

See ya soon.

  • TallBoysWRF

Posted January 18, 2006 - 11:14 AM


As I was saying before, if you run the vent hose up, you will probably take care of the problem. Think about it this way, if you leave the hose as is, the oil has to go about an inch and a half up to get over the 'loop' in the line. From there gravity takes over and the oil runs down the hose and all over. If you run the hose up, then the oil has to spit up agains gravity about a foot and a half through the hose, and gravity is pulling the oil back down to the motor. :bonk: Just be sure to put a filter of some kind on the end of the hose to keep the crud out. Most anyfilter would work since it doesn't need to be a high volume thing since it's only a vent hose. You don't have THAT much airflow coming out that hose, you have cams spinning at X thousand RPM and that's what will throw the oil up into the hose. I'm not trying to bash you with this, it just sounded like I needed to give a little more of an explaination. :thumbsup: Hope you get it figured out.

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  • steve lemley

Posted January 18, 2006 - 11:19 AM


Got it. Ill rig something up and if it works okay, Ill take some pics and post them for others in the future... :thumbsup:

  • steve lemley

Posted January 20, 2006 - 07:40 AM


Ive added the crankcase breather to approx. 2 feet of hose and re routed the line to just next to the dip stick. Im going on a 3 day trip this weekend and will have a difinite answer on whether it stops the oil drip. Total cost $6.00. It came out really nice and was easy. Ill post pics of it on monday:)))))

  • Indy_WR450

Posted January 20, 2006 - 07:43 AM


Dont forget that whenever you crash oil in the head will most likely flow into the breather and reduce some of your oil volume more than the occasional drip. :thumbsup:

  • bhavenst

Posted January 20, 2006 - 08:18 AM


My breather hose was relocated (by the previous owner) so that it ends in a one-way duck bill type valve that sits just above the chain. The one-way valve prevents water ingestion, and the drippage lubes the chain. Seems like a good idea to me.

  • byggd

Posted January 20, 2006 - 08:54 AM


My breather hose was relocated (by the previous owner) so that it ends in a one-way duck bill type valve that sits just above the chain. The one-way valve prevents water ingestion, and the drippage lubes the chain. Seems like a good idea to me.

Most of the wr/yz chains are an o-ring style so lubing serves no purpose and only increases the collection of dirt on the chain :thumbsup:

  • steve lemley

Posted January 20, 2006 - 10:54 AM


wait you mean I dont have to spray my chain every time I ride????? No lubing at all nessisary?

  • TallBoysWRF

Posted January 20, 2006 - 12:07 PM


Technically, no, although it is a good idea to keep the o-rings lubed and the chain will run quieter if you spray some lube on it. I don't spray mine down everytime I ride, just after I wash the bike or have been fording creeks to keep it from rusting, and to help with what I said above. :thumbsup:

  • byggd

Posted January 20, 2006 - 02:00 PM


wait you mean I dont have to spray my chain every time I ride????? No lubing at all nessisary?

That is correct as long as the chain hasn't been replaced with a cheaper, non-o-ring type. After I wash my bike I clean the chain with WD40 and then wipe back off as much as I can. Some say it's good/ok to spray it with a dry lube but I never do.

  • steve lemley

Posted January 22, 2006 - 09:24 PM


Okay. Im back from my 3 dayer out at Johnson Valley for the Hair and hound AMA national desert race and it was a blast. I found a peak at the top of a huge sand dune at had a view of a mile at least. They flew within 10 feet of me. What a rush!!! Back to the oil rerouting issue. The oil line was rerouted to the top, next to the dip stick and attached with a breather. It worked perfect. No oil drips at all and no leakage at all. I layed the bike down once in the sand dunes and high sided once on a hill climb so despite my bad riding the oil issue was put to a pretty good test. This should be one of the musts in the free mods catagory. Ill post pics when i can.

  • pops 56

Posted January 23, 2006 - 02:45 AM


Hi Steve Lemley. I have done the same with my breather works well I prefer to have the oil drip on the chain than on the ground.http://i47.photobuck...56/breather.jpg


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