99 WR 400 Question

7 replies to this topic
  • desert_racer

Posted June 10, 2004 - 02:14 PM


I have searched hi and low and checked the thumperfaq site but still cannot find the answer I need.

When de-octopussing the carb do you plug the two inlets (one on the front left side and one on the rear left side of the carb) or do you run a hose connecting the two.

Any help would be appreciated.


  • SXP

Posted June 10, 2004 - 06:22 PM


Here you go. This is how the left side of my deoctopussed '99WR 400 carb looks:
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  • MN_Kevin

Posted June 10, 2004 - 07:40 PM


On my 99, I USED to run the rubber vacuum caps.

After looking at the dryrot, I (after doing lots of plumbing work on my house) opted to silver soldier the nipples. I filed them down a bit to make them less obtrusive, then FILLED THEM UP!!

Nary a leak...and NO DRY ROT!! :thumbsup:

  • The_Missile

Posted June 10, 2004 - 09:27 PM


What you have done is right.

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  • toolie

Posted June 11, 2004 - 03:33 AM


So after de-octopussing are there any jetting changes required? What are the benefits to this, those who have done this mod have you noticed any improvments? :thumbsup:

  • desert_racer

Posted June 11, 2004 - 05:08 AM


Excellent info guys. I really appreciate it.



  • tcmII

Posted June 11, 2004 - 08:48 AM


Check out this link to thumperfaq thumperfaq acv there are some more pictures and information on different ways to disable the air cutoff valve. One of them will likely work for you.

Also, I am pretty sure I read a JD response that you will need to change some pilot air jets after the de-octopuss. You should be able to do a search to find it.

  • MN_Kevin

Posted June 11, 2004 - 02:48 PM


What are the benefits to this

IMHO the BIG thing is reliability. All those hoses are a disaster waiting to happen, if you happen to snag one.

The YZ carb was the same EXCEPT for the octopus. The WR was plagued w/ jetting problems. Between the octopus and the retarded exhaust cam timing, it wrecked a great running engine.


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