99 yz 400

2 replies to this topic
  • del III

Posted April 12, 2010 - 06:29 PM


i just got a 99 yz 400 it was leakin oil so bad i couldant ride it more than 5 miles. I fixed that problem now its blowin oil out the breather tube is there a way i can fix that

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  • DeeCee

Posted April 12, 2010 - 06:48 PM


How much oil is in the bike ?

YZ400's always blow a little oil out the breather (usually a small patch on the ground after a ride).

If it is blowing a lot out of the breather it is either overfull with oil or you are pressurising the crankcase which is probably due to leakage past the piston rings.

  • del III

Posted April 13, 2010 - 07:27 AM


i put 1.6 courts into it i got that out of the book. i rode the desert 100. when i was done there was some blow back on my frame & swing arm. & i had to put in about a 3rd of a court to top it off after my first 50 mile lap there is no motor noise or piston slap to indicate bad rings

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