Jetting - Popping on decleration


I am haiving some problems with the jetting on my 01 WR426 with WHite Bros S Bend muffler. Current setup

MJ 165

DTM #2

PJ 42

FS 1 3/4 turns

I get hesitation at 0-1/2 throttle and load popping on deceleration. I thought it was running lean but removing the air filter makes it run better. Not sure where to go from here?



Just to let you know I have searched the archives looking for some answers or ideas but have hit the wall so to speak.

Hoping that someone can at least point me in the right direction of where to go next.

Try DTM#3 despite your air filter results. This is a more common position to be at. It is very rare to see a 426 with the DTM, the WR400 used it standard for the US models.

agree the needle and also go down on the PJ to 40 and also do the BK mod.

you may find that the needle can go up 2 or 3 clips.


I will have to check my clip position as I think I have worked it out wrong. I moved the clip up from #3 to make it leaner. This would make it #2 or #4?

I bought the bike with this jetting as done by the shop for my exhaust. I believe the standard needle here is Aus is a OBDQR(not sure what this equates to ie DTM)

I found a post saying that the OBELN needle # 3 clip position was good. Would this be a better needle to run?

Talk about a sharp learning curve!



Looks like hitting my back button repeated the post.


[ July 01, 2002: Message edited by: bigal_wr426 ]

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