Throttle Stop...How much to cut ????????

Took out Throttle Stop of my new '05 WR450F.

Total length 33 mm.

How much do I have to cut ?

In it's said to shorten it to 25 mm total, but that web site I think is just for WR250F, models '03 or older. :):)

Need some advise.

Thank you. :D

I found it doesn't matter. Just leave a little above the treads and put it back in. You only need to have it in to keep dirt out.

You discovered a very important issue: "It doesn't matter the exact total lenght, just shorten it a bit". :):)

That is a very diferent and easier approach.

Gona cut it tonite.

Thank you so much. :D

i think the length is 18 mm- I saw that in the free mod secion for the 250

I actually cut it last nite to 20mm.

Does it matter 2mm longer ?? :)

Thank you.


i do not think so- it just means you are going to a little less throttle- than a guy with a YZ throttle screw- That is such a small amount I would not worry- You can always go back later and cut 2mm off of it- Or get a YZ screw (about 7 bucks)

I know it made a major difference with my bike- It is so nice to come out of a corner, whack that throttle open, spin the tire, pull the front end up and get set for the next corner. the free mods really changed the bike-

You want the bottom of the slide to be flush with the top of the intake when the throttle is wide open. No more No less

Rode it today for a while after cutting the Throttle Stop, it fly like a rocket on 3rd, 4th & 5th.

Don´t need the extra 2mm !!!

Thank you.

Rode it today for a while after cutting the Throttle Stop, it fly like a rocket on 3rd, 4th & 5th.

Don´t need the extra 2mm !!!

Thank you.

It makes a huge difference when you cut the stop. If you are like me you will ride it for a while then start looking for more power with some other mod :)

Lets see, say your only getting 7/8 throttle, take about 45 hp x .125 = 5.625 hp lost. There's people on here that would trade there wife for this much hp that cheap :):D:):D:worthy::D:D

When I picked up my '05 I asked the guy about the screw and what is the best way to approach it. He said alot of guys are just taking it out and leaving it that way. But he strongly advised against it because he said the needle can actually slip out of the jet and get stuck leaving the throttle wide open. So i just went out and bought the YZ screw, it was very cheap, and VERY worth it. And the throttle did actually stick on me one time. It took about 10 minutes of jiggling the throttle to get it unstuck, but I havent had a problem since. Id say just for safety and surety go out and buy the YZ screw. If its too long your losing HP (believe me it will make a difference when your climbing up the face of a mountain and you need that last 1/8 at the higher RPM's to get you to the top). And if it's too short you risk your throttle sticking.

Crystal Clear !!!! :):D

My next move (after Re-Jetting) will be buying the YZ throttle stop and the AIS Kit (to take out the bolts and rubber plugs I used on the AIS hoses).

Heard there is a Kit that brings all those things together, wich one do you recomend ? :D

Thank you to all of you. :)

Hey freestyle250, when you say that the throttle actually did stick on you once, was that when you had completely removed the throttle stop, or when you had the YZ stop in? A stuck open throttle is our worst nightmare and I want to know if it actually stuck on you WITH the throttle stop in. :D

I hacked my '05 WR450 Throttle stop down to the YZ spec, and of course it did turn the WR into a beast. :)

Is this fix applicable to WRs in all countries or did some countries get WRs with the shorter throttle stop?

I ride with freestyle250 and he was running with the YZ stop when the throttle stuck open. It only happened one time, and believe me, he hasn't babied it since then :-) , so it must have been a fluke.

If you cut off too much you can damage your AP lever, and the constant banging of the slide against the top of the carb body can crack the casting.

Just buy the YZ part.

Keep in mind that some measurements are counting ONLY the threaded portion and not the head. IIRC, the 18mm measurement is not including the head. The YZ screw is about 23mm overall (including the head).

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