2001 yz426 jetting (sea level)

6 replies to this topic
  • keegan1014

Posted March 24, 2009 - 02:03 PM


I did do the search ( I promise)
Im at sea level and getting a continous poping on deceleration
pulled the bottom off the carb yesterday this is what I found.

main 162
pilot 42
f/m screw 1.75

does it hot and cold full throttle to 1/4 throttle thinking im lean
but any help would be appreciated.
stock exhaust
air box has no lid not sure if there should be one or not

  • grayracer513

Posted March 24, 2009 - 03:11 PM


getting a continous poping on deceleration

does it hot and cold full throttle to 1/4 throttle thinking im lean

These two statements disagree with each other. Are you decelerating, or are you at 1/4 to full throttle?

  • keegan1014

Posted March 24, 2009 - 03:15 PM


What I ment was at any throttle poss. when I roll of
(close the throttle) it always pops until it drops to idle.

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  • grayracer513

Posted March 24, 2009 - 03:26 PM


And you read through this?:


Check the exhaust for leaks first.

Then read:




After that, go to the User Jetting DB and locate someone with a set up as close to yours as possible in terms of equipment. Correct for the altitude by changing the jet size by 1% larger for each 1000 feet lower your altitude is than theirs.

  • keegan1014

Posted March 24, 2009 - 03:28 PM


will do thanks

  • keegan1014

Posted March 29, 2009 - 03:05 PM


changed pilot jet to a 45 good to go thanks

  • DrThumper

Posted March 30, 2009 - 07:45 AM


I have a 2000. All I did when I lived in San Diego and rode the mtns and desert down there was went down one size in the pilot. Thats it. I moved up here where I ride 4500-10,000 ft and all I did was to lower the needle one clip position. I tried the 2001 needle as someone suggested that years ago, but eventually went back to the stock. Now it's pretty damn lean at sea level, but still rideable, but not lean enough to change it out for the little time I spend down there.

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