01 yz 426 fuel mixture screw on the carb, HELP

4 replies to this topic
  • Ilikecamarosanddirtbikes

Posted April 26, 2004 - 06:07 PM


I need to adjust the fuel/air mixture on my carb because it is running way to rich. I can't find it on my carb though anyone know where it is on the carb. What should I adjust it to if I am running at around 650 ft. elevation (chicago). Just checking, if my bike is having problems with starting the bike when its hot, and it stalls when I let off the throttle or accelarate from an idle to abruptly, its running way to rich right? :)

  • rucka356

Posted April 26, 2004 - 06:52 PM


hey man, look on the bottom,its hidden away in a hole in the bottom of the carb. Turn it all the way in and count how many turns you turned it. If its at stock, then it will be about1 7/8 turns out. If thats to rich then go to 1.5 turns out. And if thats to rich then turn it to 1.25 turns out. Be sure and start by turning it all the way in like your tightening it to see how far out it was at first though. You will need a super small flathead screwdriver to turn it. Its small and hidden away in the bottom very good. Its more towards the motor side of the carb then the air filter side too. Look in ur manual or an online micro ficsh if you can't find it.

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  • work4matt

Posted April 26, 2004 - 11:52 PM


I thought turning the screw in richened the mixture not leaned it out!

  • sirthumpalot

Posted April 27, 2004 - 01:18 AM


I thought turning the screw in richened the mixture not leaned it out!

If the carb has an AIR screw then turning it in (less air) effectively richens the mix. On these carbs it's a FUEL screw, turning it in leans it out.

I highly recommend something like the ZipTy Fuel Screw. A must have if you adjust the fuel screw more than once in your life!

  • thelimey1

Posted April 27, 2004 - 02:56 AM


or go to motomans website, you can make a free fuel screw extender so it pokes out of the bottom of the carb. he uses a piece of automotive brakeline. ive used mine on my last 2 bikes, works great

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