Need help with throttle trimming on my WR426F

Should the throttle stop be trimmed to 23mm. And I heard something about that measurement including the allen head, I saw a pic after the mod was done but it looked like the throttle stop threaded into the carb? So is the measurement to the end of the threads or the nut where the wrench goes OR does it actually have a allen head tip that I will be able to see once I get the cover off?


The entire overall length (including the head)should be 23mm.

If you are gun shy about hacking your stop, order a throttle stop for the YZ 426. It fits perfectly.


If you had an xr600r you wouldn't need to trim no throttle stop!! ma

Not to be evil, but the reason your Xr doesnt have one is because it doesnt have a real carburetor. It has s nice design flaw in the butterfly. Wait till you suck it in your engine.. and the simple throttle stop (filing or replacing with a Yz throttle stop) doesnt sound so bad. The Wr is the only model that has it.

besides.. Its to make the bike "legal".. because it makes so much more power than its displacement suggests.


Jemtec: Sorry about that Ma's XR600 is a buddy of mine and he's just giving me a little grief. That wasn't meant for anyone else. But I'm glad to see us 426ers stay together :)

I pulled my throttle stop out and put a little-dab of clear silicon in the hole (just to keep dirt and water out). My '01 WR is running problems yet.


I'm NOT convinced taking other folks's measurements is necessarily the way to go. Not because the 23mm is wrong, but it's hard to convince myself to take other folks's numbers--especially when several different figures have been tossed out. it seems the lenght COULD BE (not 100% sure) different from year to year as well.

And whoever removes this stop, don't complain about WOT hesitation, cracked throttle slides, or fatigued needle orifices. DO NOT REMOVE THIS!!!! If it wasn't required, why does the YZ have a stop as well (albeit stops at full thottle). I know, I know "you're shop did this" or "it was easier". Who do you want to believe, you're own eyes or a mechanic?

The only real way to cut the stop is do this:

Raise the rear subframe and airbox so you can see the inside of the rear portion of the carb. Cut the stop so the bottom of the slide is flush with the carb bottom. it's easy to tell once you're there.

Hopefully my FAQ will end this once and for all :)

Good luck, 696.

AS I have advocated in the past you need to cut you throttle stop just enough to allow full opening of the carb throat. This means look into the carb airhorn open the throttle and see where the slide stops you want to cut off just enough to allow the slide to stop at the very top of the carb throat and no more. As in my case it may take a coupe of trys to get it perfect so don't cut off too much on the first attempt! Over opening the throttle may or may not cause a problem with the ignition mapping due to the TPS input.

So don't take a chance regradless of what some dealer or your budy says and cut it to the proper length or install the YZ stop and check it.



Ok, it done and forgotten. I just cut it to 23mm and when I grease my frame I check it then.....There's no need to reply to his post, please let it die in peace :D:D:)


Dont worry 696, Im not ticked or anything. I understand the "grief" factor friends can create. :) I just never appreciate statements that say that a bike is junk because it has an odd "addition" to this or that. Thats like saying a bike is junk because the rider is a retard. LOL. Anyway, No biggee. Thanks for the post.

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