The 2001 Throttle stop

21 replies to this topic
  • Bruce_in_Phoenix

Posted February 07, 2001 - 08:33 PM


Anyone have it figured out yet? I took off almost 10mm and it feel like it needs more. I hate removing the carb so I just cut some like they did on the 2000's. My 99 felt stronger than this new one. Someone who has had their carb off and measured the exact length necessary to remove or leave would be appreciated. BTW the suspension on these 2001's is very very sweet. I don't think I will be Race Teching this one for a grand this time around. Also if anyone in the Arizona area has pinpointed jetting I am still getting a hesitation just off idle when I crack the throttle?

  • Guest_Guest_*

Posted February 07, 2001 - 11:13 PM


I cut mine with a pair of linesman pliars and ened taking off over 12 mm. I pegged it in 3rd to see what happens and I hit the rev limmiter, that's it. No propbems as of yet.

  • Guest_Guest_*

Posted February 08, 2001 - 01:14 AM


I haven't put mine in yet, as I have had no problems with it out. My dealer took it out before I picked the bike up, and when I queried him, said that they always remove them before selling the bikes. The service manager told me that he has had no complaints from anyone, and that I was the first one to come in and ask for the throttle stop. Has anyone actually had a problem with a 2001 WR426 because it had no throttle stop??

  • Dan_Lorenze

Posted February 08, 2001 - 07:41 AM


S-pad, I have a Canadian WR426. My bike did not come with a throttle stop and my bike seems to run fine. The only thing that concerns me is that the airbox makes alot of noise kinda like Im running it without a filter, could this be because the stock pipe is sooo quiet that I notice it more? It makes a WHaaaaaa,WHaaaaaa sound under my seat??????? Is that normal? My 98 WR400 does not do this. Dan

  • rwhitlock

Posted February 08, 2001 - 08:02 AM


I too have the '01 WR426. My dealer took the entire stop off. This has had no negative effects in my riding so far, but then I have not been on full throttle for more that 2 or 3 seconds at a time (snowy conditions....).

However, I did order (and recieve) a '01 YZ426F throttle stop. It is much shorter than the WR, but I do not have any metric measuring devices to tell just how much shorter.

I will be pulling the carb off and putting the new one in, then checking to see if the slide still goes past the top...



  • Bruce_in_Phoenix

Posted February 08, 2001 - 06:28 PM


So what I am hearing is that nobody has a measurment for me yet. Measure the total length of the YZ stop including the head with an inch ruler if you have to and give it to me in 16ths of an inch. I just want to see how close I have come and not pull the carb if I don't have to. Thanx

  • dwby2kwr

Posted February 08, 2001 - 06:56 PM


I have a 2000 wr and I took mine clear out with no ill affects. the dealer told me to just put a little dab of silicon over the hole in the carb to keep dirt out. works fine for me.

y2k wr, 13 tooth front,
airbox lid and baffle removed, 180 main, 45 pilot, 426yz er needle,
wr timing

  • Guest_Guest_*

Posted February 09, 2001 - 12:51 AM


Dan Lorenze: I only ran my bike about 1000 yards before I decided that the plug needed to come out of the muffler, so I'm not sure how much noise is coming from the air intake. I removed the airbox lid as well. Not sure about the Canadian model, but taking the plug out of the US model makes a big difference.

The throttle stop (or lack thereof) is covered with a plastic cover that also covers the throttle cable pulley on the 2001 model, so there is no need to plug the hole if you take out the stop. I guess the 2000 carb is slightly different?

  • darbsitton

Posted February 09, 2001 - 04:08 AM


I cut off 7.5mm and verified that the throttle was opening all of the way by pulling the airbox/carburator boot off and peaking inside the carb while the wife opened the throttle. If you want to verify for yourself, pulling the boot off only takes a couple of minutes and does not require removing the carburator.

  • Guest_Guest_*

Posted February 09, 2001 - 10:47 PM


I had my carb out last night and trimmed and ground the throttle stop screw by .350 inches (8.89mm) for a remaining length of .955 inches (24.26mm) as measured with calipers. Based on a previous post, I would say that as long as you stay between 7.5mm to 8.9mm you will have full throttle opening, with the throttle valve clearing the venturi without the needle retaining screw hitting the top of the carb.
If you completely remove the screw, every time you are WOT, the sharp edge of the allen screw which holds the jet needle in will contact the top of the carb (valve lever housing cover) nicking it. This is not a good thing!
I hope this helps.

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  • Bruce_in_Phoenix

Posted February 09, 2001 - 01:11 PM


Exactly what I wanted to know. I cut off 10mm the other day and I was right in doing so. Thanks a lot guys. The issue is considered resolved. Unless...........

  • JamesD

Posted February 12, 2001 - 01:08 PM


I cut more off of my 2000WR throttle stop than I was supposed to with no ill effects.

  • Guest_Guest_*

Posted February 13, 2001 - 04:34 PM


I'm still trying to find it!


Posted February 13, 2001 - 09:41 PM


Bruce- Go back to a post by finglan 1-16-01
and followed by a response from RAZOR.
OH HELL, I'll save you the leg work.
You'll need to take off at least 11.5mm in order for the slide to be flush with the top of the venturi at WOT.

  • Coop39

Posted February 16, 2001 - 07:30 PM


18.5 mm from the treads to the end of the pin, not counting the allen head.

  • Powerband

Posted February 22, 2001 - 05:52 PM


In the March 2001 edition of Dirt Bike magazine, they have reviewed the 01wr426f. They indicate in the review on page 48 to file down the limiter to 23mm including the allen head.

  • JamesD

Posted February 23, 2001 - 12:05 PM


And the previous year's Dirt Bike magazine gave the wrong amount to cut off the 2000 throttle stop. I wouldn't trust it.

  • jj

Posted February 23, 2001 - 01:33 PM


I agree with what Phil said above. I tried some elses measurement, it was wrong. Pull off your carb and check how far YOUR stop has got to get cut down to allow the slide to just clear the edge of the venturi.

JJ from WA - 99 WR; WR timed, EKN Needle, Scotts stabalizer, Scotts triple clamps, Pro-Tapers, Michelin S-12's, Terry Cable hot start, MSR Raptor clutch lever, Moose skid plate, Works frame guards, Acerbis Pro Rally guards, Renthal MD-soft grips, Factory Effex graphics, YZ IMS seat base, YZ Factory Effex seat foam and gripper seat cover, YZ rear fender

  • pthunborg

Posted March 12, 2001 - 08:41 AM


When I saw the picture they provided on page 48 in the March 2001 Dirt Bike, I laughed. They are pointing at the stop for when the throttle is CLOSED, not the WOT limiter. They really messed up on that one!!!


  • ow595

Posted May 19, 2002 - 09:56 PM


Anyone modify a 2002 WR426 yet.
I'm de-restricting my buddies WR and when I removed the throttle stop it was slightly under 1 inch (25.4mm) in total. From reading other posts that sounds like the corrct length for full throttle? does this sound right?
Also I did not see a grey wire from the CDI box but I do see a place where a wire is missing. Are the late 2002 models already partialy de-ristricted?
I did just removed the airbox top and muffler insert (too loud though...need to work on that).

William Ow
Santa Cruz, Ca


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