"99"YZ400F Radiator Problems

4 replies to this topic
  • will neuhaus

Posted August 18, 2011 - 06:52 AM


Yesterday I ran my 400 around the yard and then got off of it and let it idle with a few revv's to hear the noise difference in the White Brother's exhaust system. Looked below the motor and saw the coolant running down and out of the overflow. Supposed to go to the track on Sat and not sure if I should now! Any suggestions? The water pump has not been rebuilt and dont have enough time to do it before sat. Read up on a few thread's and saw where this is a common problem and could possibly be something as simple as going with a higher pressured radiator cap? Do not want to run hot..........

  • GCannon

Posted August 18, 2011 - 07:20 AM


Go to Auto parts store and buy a radiator cap for a 2000 Ford Ranger 3.0 V6 and put it on you should be good to go.

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  • dgcars

Posted August 18, 2011 - 08:02 AM


Don't forget...the longer you have the motor running on the stand the more likely it is to spill from the overflow.

  • will neuhaus

Posted August 18, 2011 - 09:29 AM


Ok guys! I did replace the cap with the "00" ford ranger radiator cap. The cap itself is has the same pressure rating as the original cap on the bike (1.1). Bike heated up=No leaks! Dgcars, thanks for the reminder of not letting bike idle on stand as they do not like this type of non-action! Thanks guys and thank God for Thumper Talk!!!

  • will neuhaus

Posted August 18, 2011 - 09:44 AM


Btw, the radiator cap cost me $7.48 at Oreilly's auto parts store.


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