WR Carb. Problems

5 replies to this topic
  • snowman02

Posted October 25, 2005 - 12:12 PM


I had just purchased an 02 WR426. I have been doing some reading on mods for this bike, and I have done just a few of them. I cut down the throttle stop, cut open the air cleaner lid and put a FMF powercore 4 exhaust on. Now the problem. The bike is street legal and I have not had a chance to take it out in the dirt as of yet, but I did ride it around town. So far it starts fine, even when warm, but if you back off of throttle it stats a little back firing and at idle if you snap throttle it will try to die. If you have RPM's up in nuetral and left off throttle it will cough and die. This is my first four stroke, so my first thought is air/fuel mixture. adjust air screw first before playing with any jetting. If this is correct, any suggestions as to where to start with screw turns.

Thank you all.
P.S. I live in the Arizona Desert 300 Ft. A.S.L. if this should help. :banghead:

  • ARin

Posted October 25, 2005 - 04:53 PM


sounds lean from all of the uncorking you did.

probably needs a full rejet, but try backing out the fuel screw a half turn...see what that does.

  • WR450F_RDR

Posted October 25, 2005 - 06:08 PM


have to agree, sounds lean. what are your needle and clip settings?

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • snowman02

Posted October 25, 2005 - 07:41 PM


I would assume stock, because I just purchased the bike about a month ago, and I was told it was stock, but you know how that goes, never assume right. I will try to check out what my jetts are in the next few days. Thank you. I don't want to sound stupid and all, but on this bike I do need to pull the carb off to check the jetts?? Can't just turn the carb to access float bowl like on older bikes??

Again thanks

  • ARin

Posted October 25, 2005 - 10:16 PM


I have pretty good luck with loosening both boots, and working the front boot off...leaving the intake boot on...and pushing the carb toward the left side of the bike. Gives you sufficient access to the bowl, and the needle.

  • new2blu

Posted October 26, 2005 - 03:33 AM


It sounds lean to me. A quick check would be to turn on the cold start knob (choke) while you are riding in 2nd or 3rd gear and see if the poping goes away. If it goes away richening the jetting will fix the problem.


Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.