1999 yz 400f oil leak

3 replies to this topic
  • ryan2214

Posted October 18, 2008 - 07:03 AM


I just purchased a 1999 yz 400f (got it for a great price). I noitced after the engine has been running for about five minutes and I shut it down about one to two drops of oil slowly leak out of the overflow tube. Is this normal? I just changed the oil and I am sure I put the right amount back in. Also I went riding yesterday with my six year old so there were times I was going really slow or even stopped and ideling, I noticed the radiator was overheating and spewing steam out of a line at the bottom of the radiator. Is this normal? I don't have an owners manuel, but I am in the process of looking for one. I went to our local shop yeaterday and they told me they are discontinued.


  • VB_Racing

Posted October 18, 2008 - 07:36 AM


The oil drips are pretty normal, the overheating was pretty common on those old bikes also. Check your radiator cap to make sure it is holding pressure, you may be able to get a heavier cap. Make sure your coolant is clean, and that the radiator isn't full of silicon drop out, from old coolant. It may be a good time for a coolant change also.
The oil dripping out of the breather is fine, my 08 YZ does that also, overfilling the oil will make it worse.


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  • ryan2214

Posted October 18, 2008 - 07:40 AM


Thanks for the info Dave. Also until I get the manuel I may have some more questions like what type of coolant to use. Water to coolant ratio?

  • grayracer513

Posted October 18, 2008 - 08:13 AM


You might want to visit the Common Threads Sticky



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