98 yz400f leaking oil from breather tube

6 replies to this topic
  • Wanny14c

Posted July 21, 2015 - 05:00 PM


Hello guys I just bought my first dirt bike and as you can tell by the title I have a little oil leaking from the breather tube is this normal? It's not a lot and it is clean oil not milky. Just want to make sure I'm not going to wreck the bike. I have read some of the other post about the same issue and was talking about oil blow by and that if the bike was running good not to worry about it. Is this true?

  • Wanny14c

Posted July 22, 2015 - 07:33 PM


Any one?

  • 03yzf450-kuke

Posted July 23, 2015 - 08:14 AM


Could just be from simply over filling oil

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  • grayracer513

Posted July 23, 2015 - 08:24 AM


A search would turn up hundreds of results on this subject, but I'm surprised that no one else has given you any sort of definitive answer.


"Some" oil will almost always drip from the breather, particularly on an older engine that is probably leaking more combustion gasses past the rings.  Overfilling the engine will increase that, as said, but most of it is normal as long as there is not also a measurable loss of oil.

  • Wanny14c

Posted July 23, 2015 - 10:23 AM


Thanks guys it's only about 4 drops after every ride and it does seem to be a little bit high on the dip stick. I appreciate the comments.

  • flymikemc

Posted August 05, 2015 - 08:20 PM


I have the same bike and it drips about like yours.  It seems to go through quite a bit of oil.  I'd guess Probably about 1/2 quart per 3-4 hrs of riding.  I've only had the bike  a few months and noticed the same 3 or 4 drips of oil on the floor after riding and then noticed the oil use.  It doesn't smoke or anything it just likes to use oil I guess.  I gather I need to do that search the other poster suggested.  

  • mediumdaddy

Posted August 17, 2015 - 12:58 PM


Mine leaks some to. i even had the top end rebuilt to try and stop it, but it didnt stop. The bike runs better though!

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