New guy info & Throttle stop screw question

Hello all, I've been "lurking" on this site for over a year now, I used to pop-in from time to time, mostly in the Supermotard forum, just to see what was going on here. This place seems to have more "technical information" (and arguments regarding it :thumbsup:) than most other sites i've seen. Some here might know me from Speedzilla, Visordown, or MonoManiacs as "Jacka$$". I had purchased a 2K1 KTM LC4 640 Supermoto in July of 2002, & converted it to the "Stealth Motard" that some who frequent the other sites listed above may have seen. After having the Supermoto & deciding that it would likely get me into more trouble riding on the street than I was willing to deal with, I decided to sell it & but a "real dirt bike", so I ended up buying a new '04 WR450 a few weeks ago. This is where my question comes in:

I have looked all over & tried to find an actual length for the '04 YZ450 throttle stop screw & have'nt had any results. Most people say to just cut the unthreaded portion of the WR screw off & that's it, but I've also seen some posts about problems with cutting it too short (or maybe they left it out alltogether?).

Does anyone know what the length of the cut screw should be? Or do I just dremel off the unthreaded portion & call it good?


wow, another st.louis area guy with a wr450. sure seems like there's a bunch of us. two choices. you can buy the yz throttle stop, or cut yours. i don't have the "exact" length, but don't cut all but the threads off. there was a service bulletin for the '03 that had the numbers. i'm suprised the dealer didn't do it or at least tell you. check out and find the wr450 project bike. there's more info there.

Yeah, I looked at that but they just say to order the YZ one. Thanks, but I'd prefer not to spend $18 on a part I can just modify.


"Take the throttle stop out and throw it at a target, then pick it up and deposit it in a clearly marked recycle bin. One can never be too careful with things that might harm our environment. Then head over to your Yamaha dealer and get an YZ426~450 throttle stop part# 5JG-14591-00-00. This stop is shorter in length and will let you achieve full throttle."

Has anyone on here bought the YZ throttle stop & measured it?

Well, I guess I just did'nt search hard enough before...

According to these threads on this site, the screw should be either .910" long, or 11mm shorter than the stock WR one.

it is my understanding from a post long ago that the proper lenght is 23mm.

Your dealer has atech bulletin with the correct length listed....I'd ask them if I wanted the correct answer.....


I called my dealer & asked the guy in the service department if they had a service bulletin that gave the length of the YZ throttle stop for '04, as I had bought a WR from them a few weeks ago & would like to know how much of the screw to cut off. He said, "I've never heard of anybody doing that to the '04. We have several guys around here & none of them have done it that I know of... Anyway, I was told I'm not supposed to give that information out because it's a liability." :thumbsup: I then asked if he knew if there were different part #'s for the 04 WR & YZ screws, & he transferd me to parts, where I sat on hold for 10 minutes & finally hung up. Funny thing about his comments was that the owner of the shop (who I should have called, I suppose) told me to cut all of the un-threaded portion of the screw off back when I bought the bike.


Is anybody on really good terms with their local Yamaha Dealer?

I'm now begning to see why people have just ordered the YZ part, even when it costs $15-$20. :devil:

Edit: I was able to determine that the 04 WR & YZ do indeed have different part #'s thanks to the Yamaha Online Parts Catalog.

okay, you've been chewing on this for about a week now. why don't you just cut a little off and see if it's enough. if not cut some more. the idea is to allow the slide to open enough to use the entire carb bore. it might take a couple tries to get it but it'll be worth it.

Mostly because I don't have the time. Hell, I bought the bike almost 4 weeks ago (as of this Saturday) & the only place I've ridden it is up & down the alley behind my house! I've got too much work to do on my house, but in a week or two I'll hopefully have the time to do all the mods to the bike & take her for a ride. I'm trying to figure out what it is that I need to do, so I only have to do it once & not mess anything up. :thumbsup:

BTW, I see you're in brentwood, where do you do most of you're riding? Most everyone I know goes to Flat River, St Joe, or some place in Coulterville, IL.

I say if you that short on time, quit screwing around! Get the factory throttle stop, do the other mods and get out some where. :thumbsup:

Or don't do anything, I have to believe that the stock bike is fast enough for your alley!! :devil:

didn't mean to come off too harsh. your probably riding as much as i am right now. i started riding my WR to work just to get some seat time. i work at sunnen in maplewood so it's only two miles. (i love the looks i get ,though) we're working six days a week right now and it's tough to find any time. by the way, did you get a plate on yours yet. it'll help you find more riding than just st. joe.

as far as where i ride, i try to stay away from st.joe except in the winter. i do try to help with the enduro and hare scrambles down there so i can ride outside of the park some. i like to ride down at sutton's bluff near centerville. (that's where you need the plate) the club i'm part of has 600+ acres southwest of potosi i've been trying to get to when i can. (yes, it open to the public) stuff like that.

if you'd like to p.m. me, i'd be happy to give you my number. i can help you with some set-up stuff and the club property is open next weekend. a good investment, right off the top, is the gytr exhaust insert. it's about $40. the bike runs alot better than stock and it won't make your ears bleed.

No worries. Yeah, I just looked at my Bill of sale this morning on the way out the door, & came to realize that my 30 day warranty expires tommorow & I haven't even ridden it yet (aside from the alley). :thumbsup: I actually did'nt plan on getting a plate for it, allthough I do have the one from my KTM that's stickerd for april of '05, I would'nt ride on the street with it, but if it'll get me access to some dirt I'm sure I can find some zip-ties or some sort of mount. :awww: Yeah, I hear what you're saying about St. Joe, the few times I've been down there, it seems like somewhat of a breeding ground for idiots, especially given that there's bikes, quads, buggies, & 4WD's all sharing the same riding area.

As far as the gyt-r insert, I had been looking at it & the Pro Moto billet insert, but was kinda holding off, as I was going to try & get a OEM YZ exhaust, but I hear they don't have spark arrestors in them. I don't know if this is that big of a deal around here or not, but I'd be a bit pissed if I showed up somewhere to ride & they told me no 'cause my can did'nt have a screen in it. You work at Sunnen, eh? I grew up & went to high-school in maplewood (not that I'm super proud of that :devil: ). I might be trying to ride somewhere this weekend if some stuff I ordered shows up, otherwise it'll probably have to wait 'till next weekend, dunno yet. Some other guys I know from (met them through Midwest Motard in '03) were talkng about heading to coulterville, IL this weekend or next, so who knows yet. I'll shoot you a PM & we can swap #'s.


The proper length is the yz 426 - 450 part number and the right amount of corn, and the part guy gives you a little baggie with the "super go fast throttle stop" and you go home take the old one out and put the new one in. Just that eazy.

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