WR426 jetting question

4 replies to this topic
  • AliveInMyOde

Posted June 11, 2004 - 05:12 AM


hey guys
ok i need to change something because i am not getting the right response from the throttle. ok when i open the throttle fast to accelerate out of a turn it hesitates for a split second then comes the full power and its unpredictable. it goes from bad to worse as the life of the spark plug goes on. after i change the spark plug its fine but after about the 4th or 5th ride i have to change the plug again to get good response. also as the life of the spark plug goes on after i crank it and just wamr it up, it starts misfire here and there and back fires when i get on the throttle and let off real fast. i am in florida so 0 sea level. my mods r listed on the bottom. hope someone can help me with what jets to get and replace. thanks guys!


  • tcmII

Posted June 11, 2004 - 07:54 AM


Look into the JD kit. I believe that it made a difference with my bike for the better. Also, it would be helpful to understand the throttle position your having trobule. When you snap the throttle open out of a turn it's not the same a snapping the throttle open from a stopped idle. You are probably dealing with 1/2 - 3/4 throttle issues, rather than 0 - 1/4 throttle (assuming your not a slow poke like me :thumbsup:).

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  • HaremScarem

Posted June 11, 2004 - 01:41 PM


Use OBELN-3(YZ250f Option needle), 160 main, 162 main air, 40 pilot, 75 pilot air, with an home made power now valve. Do the BK mod and adjust to 1 second squirt. Do a search on the JamesNow and BK Mods.

  • miek

Posted June 12, 2004 - 03:56 PM


First get your jetting right, then you may want to consider the PowerNow or make your own version. Works great on my bike (02'wr426). Good luck.


  • AliveInMyOde

Posted June 13, 2004 - 05:47 AM


thanks guys! i'll have to try one of the kits. how much do those usually cost?



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