oil coming from vent hose on top of head

4 replies to this topic
  • XRrider62

Posted January 04, 2006 - 01:57 PM


Just wondering if someone familiar with 01 YZ426 could tell me what could be happening. When I run my yz, oil comes out of the vent hose that attaches to the top of the head. I don't have oil in the water or vise-versa. thanks for any suggestions. It's not alot of oil but it is a nuisance.

  • grayracer513

Posted January 04, 2006 - 02:02 PM


Small amounts are normal, like a few drops after a hard ride. How much is there?

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  • XRrider62

Posted January 04, 2006 - 02:12 PM


Small amounts are normal, like a few drops after a hard ride. How much is there?

Well, there's enough to make a mess on the frame. And it was'nt ridden hard at all.

  • grayracer513

Posted January 04, 2006 - 03:03 PM


When it gets to be an excess, it's usually one of two things. One is a gross overfill. This is a little harder to do accidentally with a 426 than a 450 because of where the filler is, but if you go beyond about 2qts total, it will start barfing some.

The other isn't that simple; tired rings. Too much blow by will increase the amount of outflow from the breather. New rings are the only fix. Check another one and be sure it's really excessive.

  • 642MX

Posted January 04, 2006 - 06:54 PM


Mine pukes when overfilled with oil. I don't think it hurts anything.

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