YZ400F - Do I Need a Special Tool for Spark Plug Replacement?

2 replies to this topic
  • ol_blue

Posted February 20, 2016 - 05:26 PM


Is there a special tool for this? I can't find a socket that will fit into the access hole for the spark plug. It appears that I need an ultra thin walled socket to fit inside a raised lip about 1 inch from the top of the access hole. I have tried 3 different styles of sockets but none work. 



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  • damnbiker94

Posted February 20, 2016 - 06:25 PM


I use a standard 18mm deep well socket.

  • grayracer513

Posted February 20, 2016 - 09:03 PM


The plug is 5/8" at the hex.  A standard plug socket will work, but they have to be easy enough to pull off the plug that the extension can lift it off and out of the well..  You'll need one of the extension designed to swivel a little, or a short extension/wrench combo that fits.


Motion Pro's four stroke plug socket set is a neat deal. 

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