What is clogged?

3 replies to this topic
  • firemanmatt1982

Posted April 16, 2014 - 03:52 AM


Brothers- I fired up the ol four deuce six the other day and she aint running right. Usually I take it to my shop, however at the current moment the shop is super busy and Id like to try to fix it myself. The issue is with the carb- the bike runs well with the chock on and pops and stalls out with it off. I'm sure its dirty carb issue, but I wanted to get your opinions. I believe the carb on it is a Mikuni and I'm almost sure I bought the carb from grayracer off this site a couple years ago. Anyways, tell me what your thoughts are on what the issue might be and how hard of a job it is to pull the carb off the 426! Thanks for any help

  • 1stSSPZ

Posted April 16, 2014 - 05:06 AM


Probably just a plugged pilot (low-speed) jet. Should be what looks like a plug on the bottom of the carb (17mm box wrench, if I remember right). Just take it off and using a dental type mirror, look straight up into the carb. The jet will look like a single-slot screw. Just take it out and replace it (cheap). Trying to clean one is more trouble than it's worth...

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  • orangyktmthing

Posted April 16, 2014 - 05:29 AM


Chances are that the carburetor is a keihin fcr. There is probably an obstruction in the pilot circuit. IIRC, the carburetor really isn't that difficult to remove from the bike. Pull the seat, loosen the the clamp to from the air boot to the carburetor, remove lower subframe bolts, loosen upper subframe mount and there lies the carb. From there, loosen throttle cables and then loosen the other hose clamp and pull off carb. Granted, it might just be a clogged jet, but the last thing that you want to do is go through the effort to change the jet to find out that there is some gunk in one of the carb passages that isn't allowing the low speed circuit to operate correctly. 

  • grayracer513

Posted April 16, 2014 - 06:40 AM


It's not a Mikuni, it's an FCR-MX from an '06 YZ450F.  Look for the pilot jet to be at least partly obstructed. 

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