426 carb question

6 replies to this topic
  • craigdieselmac

Posted December 07, 2008 - 03:32 PM


Does anyone else have a bead of sealant around the part of the carb above the bowl. There are 4 rounded allen head screws that hold the bottom of the carb on (viewed from the top of the carb, not the bowl screws) and around the seam there is sealant poking through. This sealant has been getting into my pilot jet on the inside and causing me hell... just wondering if a previous owner pulled some tom-foolery since sealant and gas don't mix well.
Thanks in advance

  • BC3

Posted December 07, 2008 - 08:24 PM


[COLOR="Blue"]Unfortunately backyard mechanics for years have used silicone sealer on carburetor bowl gaskets thinking that it will make that old worn out bowl gasket work better....Gasoline will attack silicone sealer and turn it into GOOP that plugs pilot and main jets and everything else it gets into.Take you carb off and clean all the silicone sealer off and buy a rebuild kit with all the gaskets needed to finish the job...Cleaning the jets in the process...Should fix the problem...I like acetone or Lacquer thinner with a short bristle brush and compressed air.... [/COLOR]

  • craigdieselmac

Posted December 08, 2008 - 05:28 AM


This is not on the bowl, its on the part of the carb that the bowl attaches to. I can't find any parts breakdowns that even show it coming off.

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  • grayracer513

Posted December 08, 2008 - 08:13 AM


Yamaha does not sell or service the gasket that goes in that joint, so if it was damaged by being disassembled, or by harsh carb dips, it may have been necessary to remove it.

Check with Sudco to see if they carry that gasket.

  • craigdieselmac

Posted December 08, 2008 - 09:20 AM


I removed it, there was sealant everywhere... all in the pilot jet passages. After some cleaning, it appears that these used to have O-ring type gaskets similar to what is around the bowl. I looked at the IPB for the carb from Keihin and it says not to take anything off that is not shown off in their picture. Gonna call around and see what I can find, if I can't get the O-rings, maybe some gas tank sealer and a little more control when it comes to sealant application. If all fails.. maybe a edelbrock carb...

  • grayracer513

Posted December 08, 2008 - 11:24 AM


Again, go to Sudco and see what you can find.

  • craigdieselmac

Posted December 08, 2008 - 11:48 AM


already did, and called them, they say the parts can't be sourced.. going to ebay to find a new carb

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