02 YZ426 Fuel Screw Setting

4 replies to this topic
  • TheRainMan

Posted November 02, 2004 - 06:22 PM


I don't have the manual - can anyone tell me what is the stock setting for the fuel screw? I'm guessing it's 1 1/2 turns out...Also, turning it in does what? Does turning it in make it leaner or richer?
Thanks :cry:

  • Satch0922

Posted November 02, 2004 - 06:39 PM


Here is the complete shop manual for the 426

426 Shop Manual

The manual states 1 1/4 turns out as the factory setting. Turning the fuel screw (or "pilot screw" as the manual refers to it) in will lean the mixture at low speeds and turning it out will richen it. Start with the factory setting and then turn it 1/4 turn increments until you have it running properly.

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  • yzf450jack

Posted November 02, 2004 - 06:50 PM


Warm up the motor first Now Turn the screw in clockwise thats leaner till it starts to run bad Now start turning it out slow (richer)counterclockwise till the motor runs smooth :cry: If you don't have a ZipTy or scotts fuel screw go get one there only about $25.00

  • TheRainMan

Posted November 02, 2004 - 07:13 PM


Thanks Satch0922 and YZF450Jack!
Is there a spark plug you would recommend besides the NGK


  • Matt96xr6

Posted November 03, 2004 - 07:21 AM



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