2002 wr426 stalling, bogging, generally unhappy

I ran into an issue with my wr426 over the weekend where it began stalling and bogging down frequently.

The stall was generally happening at idle; as I would put it in gear and give the throttle a twist the bike would bog down and stall. It also happened while heading up steep hills. I would make a corner then give it some throttle and bog..stall.

Any ideas what this could be? I bumped the idle speed up which seemed to help a little but it didn't take care of the problem. It was also a real PIA to start when this was happening..heck of a time finding tdc and required constant use of the hot start valve.

It's worth mentioning that the temp was in the mid to upper 80's here in the Northwest. I rode two weeks ago (same place) with the temps in the high 50's low 60's and the bike ran flawless.http://www.thumpertalk.com/forum/images/smilies/excuseme.gif

Could this be something in the idle circuit on the carb? Bad accelerator pump? Poor jetting? Did I drown my air cleaner in oil with recent maintenance? Any ideas or suggestions would be much appreciated.




Any ideas out there? I am wondering if it could be the jetting (stock 2002 wr 426)

I would pull the carb, give it a good cleaning, check the accelerator pump etc and take note of what jets you are currently running. Strange that it happen so suddenly so look for a air leak between the carb and head as well. My 02 has a JD jetting kit and runs well from 800-6000'.

Changed your spark plug??

start with the spark plug, and clean the carb as stated, usually the bog on acceleration is caused by a plugged AP since you didn't mess with the AP timing. Recently had that happen on a brand new 06 CRF250R that just wasn't run since day 1, just stored with the carb drained - however, draining the carb still leaves all the fuel in the AP allowing it to gum up - maybe you got a piece of dirt in the AP, but tyour issue sounds identical to the gummed up AP on the honda.

I over oiled my air filter, had all sorts of idle issue's and off idle bog.

recleaned it and re-oiled and after a couple of minutes my bike was back to normal and running strong again

hope this helps



Wow, that must have been a LOT of oil!!!!

Thanks guys. I plan on cleaning the carb (AP), pulling the plug and installing a JD jet kit since it's stock anyway. I wish I was patient enough to do them one at a time to see which one was the culprit :thumbsup:

I checked the air filter.. Over oiling was a bit of wishful thinking.

Thanks again guys..


Wow, that must have been a LOT of oil!!!!

hate to say this, but i over oiled it to the point there was oil in the bottom of the air box :thumbsup:

felt like a jackass, when i realized i betcha i didn't sqeeze the excess off..



I'll be happy if it just turns out to be a bone headed move on my part by over oiling a filter..that I now know was pre-oiled to start with!

I squeezed off the excess in the parking lot the day it happened. And there was a little puddle in the airbox... Usually the most obvious reason is the culprit, so maybe I'll get lucky :thumbsup: But then again, I was due for a re-jet from stock and carb cleaning anyway..

If you still have jetting/bogging/stalling issues I've had really good luck with the O-ring mod on my 01 426. Did the mod last year and been happy ever since. Bike will normally start cold in 1-2 kicks, and pulls like a mule off idle. Ride in Michigan around 700ft elevation.


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