Will a YZ400 Carb go staight onto a WR400F

7 replies to this topic
  • V968231

Posted July 19, 2004 - 05:06 AM


Can you kind people tell me if a 1998 YZ400 Carburettor will fit straight onto a 1998 WR400F?

Will I need any additional bits?

Will I need to disconnect anything such as the Throttle Position Sensor?

Is ther any reason why I should not fit this carb to a WR engine :thumbsup:

  • R_Little

Posted July 19, 2004 - 07:05 AM


The yz carb will fit perfectly.
The wr carb has an aircut valve for EPA purposes. Many guys remove it anyway.

  • dkwok

Posted July 20, 2004 - 12:24 PM


can u pls tell me where is the aircut off valve& how to close it?

  • The_Missile

Posted July 26, 2004 - 01:13 AM


the acv on the old 98 and 99 carbs was called the octopus. you need to remove it.

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  • V968231

Posted July 26, 2004 - 02:54 AM


the acv on the old 98 and 99 carbs was called the octopus. you need to remove it.

What is the Octopus and where can I find it?

  • The_Missile

Posted July 26, 2004 - 03:22 AM


Its a mess of pipes on the left hand side of the carb. Pull em all off and block the remaining holes with a bung.
Hook up the hot start to the tube on the cylindder head

  • V968231

Posted July 26, 2004 - 03:37 AM


Is there detailed instructions for this Mod anywhere? :thumbsup:

  • tcmII

Posted July 26, 2004 - 07:09 AM


check out "www.thumperfaq.com" or this forum. You should be able to find all of the info you need. Also keep in mind that a number of posts have indicated that you need to change your pilot air jet when de-octopussing" the carb.


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