Grey Wire & Throtle stop

Alright, somebody needs to tell this newby about the cut grey wire & the throtle stop mod. Whats this all about ??

Must be good. Actually saw it mentioned in a Cycle World article about RW426 but no details. Sounded cool, now give me the scoop.

Hi, not too sure but i ride a WR400 and the throttle stop is basically a pin that stops the throttle from turning full. Its limited to 3/4 if you don have it removed. Its easily done and be checked from the net. It does mean the RPM will act funny wit the black box if you remove it fully. Some had it trimmed. Maybe some guys will reply.

The grey wire thing i am not too sure. Whats that? Heard lots about it.

the grey wire mod or blue wire for the yz, is disconnecting the neutral indicator light on your wr. not used on the yz.

to quote Florida426:

The neutral switch in the YZ 400/426 is a remnant of the European spec models. They are sound tested rigorously over there and the test is done in neutral. The ignition mapping is set up to limit the revs in neutral so as to keep the maximum noise level down. We have them simply because it is not cost effective for Yamaha to leave them out for the U.S. / Canadian market (FP models.)

so, what happens when you disconnect it is that a bit more voltage will go to starting... :)

Let me get this straight.

I can cut the wire and it'll give more starting voltage?

Will that affect the wiring in any way?

Like in neutral? What happens?

What happen to my lights?


i would pull it out, not cut it, that way you can reconnect it if you want. i believe on the wr you will lose the neutral indicator, not sure... someone else will know ( i have a yz) it will make the bike a bit easier to start, it did on my friend's yz.

Blue wire is (transmission) neutral input- it lowers the rev limiter while trans is in neutral.

Grey wire affects your ignition QUITE DRASTICALLY somewhere around 7K rpm. Several guys have found removing the grey wire has fixed a very difficult to eliminate carb glitch. It WAS the source of the problem.

The grey wire is found ONLY ON U.S. BIKES

There ya go.. i knew someone here would know exactly! Thanks kevin! hey, any word on your head yet?

head dropped off @ UPS enroute to CA on Dec 26 / 5pm.

I know the shop is closed until 01-02 for Christmas / New Years Holiday.

Does anybody know if the throttle stop restriction also applies to European bikes?

Thanks Kevin,

My WR does not have a neutral light, If it does, I havnt found it yet. It was suggested or (maybe I understood)that the grey wire had to do with either ignition advance or rev limiter. Not sure. Is the grey wire under the tank and where exactly would I find it? Havnt probed around there much.

that's right, they are closed until the 2nd..waiting is aweful.. i hope they can fix it.. have a happy new year!

THe grey wire AND throttle stop are a USA only thing.......if your bike is UK or Euro spec you have no problem !


If I remember correctly the grey wire is paired with a black wire. There is a group of 8 to 10 wires coming out of the ignition box, the grey and black seperate theirselves from the other 6 or 8 wires. Pull it out and insulate it and you can come back at anytime and reconnect it.

Your throttle stop is screwed in the backside of the throttle cable wheel on the right hand side of the carb. You have to take off the plastic cover over the assembly. Remove the coil from the frame so you can get an allen wrench in there to unscrew it, I cut my bikes throttle stops down to 23mm but have heard others say anywhere from 21 to 25, this is the entire bolt.

Good luck, I know you'll like your bike even more with the newfound power.

Thanks Guy, I guessed not - it's way fast enough as it is!!

Hey F6dood. I did the throttle stop not long ago and it is a must do. Wasn't to difficult and I'm mostly thumbs when it comes to tinkering. There is a black cover on the right side of the carb. Take it off and just look for the allen head screw. Its pretty obvious once you start looking at it. I took it out and cut it down to 23mm with a dremel tool. I put some loctite on it when I put it back in. Like I said it is a must do. Where you riding at in the Houston area?

Hey fiveo, have not done the throttle stop or grey wire yet. Just ordered a Thunder Alley pipe and am waiting for that before I do the the free mods. But I will. I have had this bike since thanksgiving weekend and have been to the Sam Houston Nat. forest once. The trails were closed due to rain but we (the boy) cruised the dirt roads till we found the pipeline easements. Thats when then fun began. I live in Spring and there are some areas that I can get to via flood control easements just to do some jackin around. Am anxious to find some better places to ride w/ more challenging features. Also looking for a place to go for a three -five day venture. Maybe west Texas, new mexico, colorado etc. Something adjacent to Texas.Thanks for the heads up on the Mods. Where do you live? See Ya !!

I'm in Friendswood. A group of us go up to the National Forest every three or four weeks depending on the rain of course. We go to Chadwick, Missouri every year as well and are planning that now. Went out to the San Jacinto river today and found a place that looks like it might be good. Not to sandy. Gonna try that next week I think. Gonna go with a couple of guys on quads. My neighbor goes out to Skull Creek in Columbus. Its a members only riding area. I haven't been yet but I'm gonna go out with him soon. Check out The Trail Riders of Houston website if you haven't yet.


You might try 3 Palms for some riding. It's about 15 miles north of Spring at the 1488 exit. They've got a couple of MX tracks if your into that type of riding.

Also, at the dead end of E.Hardy there's alot of riding on Spring Creek. We park at the guys property on the right after the toll road bridge. He's very fair on the price to park.

You should really watch out at the Nat'l forest. If your caught riding on the roads or the pipeline easements you can get a healthy ticket. I've seen the rangers videotape riders on the pipelines then come to the parking area and look for the riders.

Send me a PM sometime and we'll go riding. I'm in The Woodlands, right up the street from you guys. When the weathers good there's some great riding in the forest. If you don't have one, call the Raven district office of Sam Houston Nat'l Forest and get a map of the PMT's (permanently marked trails)

Hey Fiveoh & Huskeyrider, After these winter monsoons pass, we'll have to hook up. I have been to Three Palms as a spectator and would be up for a blast around the track. I have also heard others speak of the Hardy Rd. area but thought it was mostly suited for quads. I'll have to check it out, only two miles from my office. The boy is excited about going three palms as he thinks he would like to race someday. We are up for road trips to cool riding places also. Let's hook up by Pvt Msg.

Lets Ride,

See Ya

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