Oil drips ????

21 replies to this topic
  • Don123

Posted October 25, 2004 - 06:17 AM


I have a 2004 WR450F with 396 miles. In the last month
after riding, I have noticed several drips of oil coming
from the large (approx 1/2" dia) rubber tube on the left-hand side of the motor. Does anyone know what this is a indication of, or is this normal?

  • Treebark

Posted October 25, 2004 - 06:30 AM


That is a crankcase vent tube. Mine has never dripped, how much is yours dripping? Possible cause could be that the rings have not broken in yet and resulting in crankcase pressure. :cry:

  • Don123

Posted October 25, 2004 - 06:33 AM


It is only 2 maybe 3 small drips, It just concerns me because it has never done this before. Maybe it's no big deal??

  • Treebark

Posted October 25, 2004 - 07:33 AM


Keep an eye on it and if it gets worse need to find an answer. I know there as been a few with this problem, do a search on this forum on vent tube and valve cover plug, not sure what's the exact name, type in plug something will come up. Some have had the these plugs pop out due to excessive crankcase pressure. Good luck

  • SXP

Posted October 25, 2004 - 10:21 AM


Completely normal on the 400/426s. Dunno about the 450... :cry:

  • coldweld

Posted October 25, 2004 - 10:45 AM


Re-route the pipe in to your airbox rubber boot problem solved.
you will never see another oil drop. :cry:

  • RichBaker

Posted October 25, 2004 - 11:00 AM


It's normal, especially if you're revving it.....don't worry unless you see a Harley-type puddle. :cry:

  • YamahaWR450FMike

Posted October 25, 2004 - 11:28 AM


That is a crankcase vent tube. Mine has never dripped, how much is yours dripping? Possible cause could be that the rings have not broken in yet and resulting in crankcase pressure. :cry:

yeah same here. 400 miles on my 04 WR450 and not one oil drip

  • Indy_WR450

Posted October 25, 2004 - 12:34 PM


Mine has never dripped. :cry:

  • jdubsooner

Posted October 25, 2004 - 01:29 PM


I have an 02 426 and mine did the same thing until i read up on how to check the oil level properly. I had been adding oil when it didn't need it and it would leak some after riding. Just glad i didn't ruin anything.

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  • YamahaSteve

Posted October 25, 2004 - 06:55 PM


mine will drip every once in awhile... not a big deal and it is normal... unless you have a puddle as previously mentioned I wouldn't worry about it. My theory is that when you are thrashing aroudn the bike and the revs are up oil gets splattered and sprayed everywhere and then when some gets close to the vent and air is rushing out for somereason it gets stuck in there; and alas you have the drips...

  • mousemeat

Posted October 26, 2004 - 12:59 AM


On my '04 450 there is already a stub-pipe on the airbox to connect the breather, complete with blanked off hose and clamp. It's quite obvious that they want you to re-route it, i'm just not sure why they dont do it. The only thing i can think of is:

Oil drips into airbox, fouls up operation: Yamaha's fault.

Bike gets started in water and fills valves with mud: customer's fault.

  • spanner

Posted October 26, 2004 - 02:26 AM


my 01 426 drops oil after every ride still runs like new

  • JMathis

Posted October 26, 2004 - 03:26 AM


The stub pipe on the left side of your airbox is the airbox drain. I don't think you want to route your vent hose to that one.

  • mousemeat

Posted October 26, 2004 - 04:16 AM


It came with a crimped off hose clamped onto it. Not much of a drain, unless i am missing something.

  • Treebark

Posted October 28, 2004 - 02:39 PM


Think, what sits at the bottom of air box? The engine will at times be under a vaccum and you will suck everything in the bottom of airbox straight into the engine. I would not connect it there, if you feel the need put it some where towards the top of airbox with a filter of some sort at the end.

  • WR_Dave

Posted October 28, 2004 - 05:01 PM


You are supposed to take the crimped off hose off of the bike during routine "maintenance" to clean the air box. Or you can put the one way check valve off of the Honda XR650 on the stub and ride with absolutely no maintenance!!! LOL just kidding guys. I still am against putting the breather vent and the carb vents into the airbox, I still prefer the "T" method. And a drip or two is perfectly normal. WR Dave. :cry:

  • coldweld

Posted October 29, 2004 - 10:04 AM


i said rubber boot :cry:
that is the rubber bit between the carb and air box.
there is a lump on the top that has to be opeded up and a jointing piece put in.
This is the official place to fit the breather pipe as listed buy Yamaha Europe.
Hope you all undersand :cry:

  • Dan_Lorenze

Posted October 29, 2004 - 10:20 AM


Completely normal. I never re-routed the hose to the airbox, I directed the hose away from my skidplate and aimed it off the side so that oil would just blow out the side of the bike and onto the dirt.

  • Treebark

Posted October 29, 2004 - 05:02 PM


Sorry I wasn't replying to you but that would be acceptable spot. I still wouldn't want to suck oil through the carb, but if I was doing alot of deep water crossing that's where I'd put it. :cry:


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