Standard Jetting for a 2000 YZ 426

3 replies to this topic
  • cooracpro

Posted April 16, 2006 - 01:40 PM


I have looked all over for the standard jetting for my 2000 YZ 426 and cant find any consistent numbers,right now I have a 178 main jet and a 48 pilot jet at 4000 foot elevation. My bike also has an aftermarket pipe on it,would that be the reason the previous owner had it jetted this way? Everything I have read about the 2000 YZ 426 says that I am about ten steps to rich.The plug is also very black so I do believe that I am on the rich side.


Posted April 28, 2006 - 07:12 AM


Carb Type: Keihin FCR-MX39
Main Jet 162
Main Air Jet 200
Jet Needle OBEKR-4
Jet Needle Clip Position 4
Pilot Air Jet 100
Pilot Jet 42
Pilot Outlet 0.9
Pilot Screw Turns Out 1 3/4
Bypass 1
Starter Jet 72

Hope that helps. :crazy:

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  • Zique

Posted April 28, 2006 - 08:12 AM


Yep, that's right...all except I thought that the main jet was 168, but I don't have my reference sheet in front of me, I'll have to double check that one, but the rest is good.

  • Zique

Posted April 28, 2006 - 08:40 PM


Yep...voodoochild is right all across the board. I was just remembering it wrong. :crazy:

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