The gray wire & jetting???

Whats the deal with the gray wire mod and how is it done? I have a 01 wr426 and i have a Big Gun race pipe and a uni air filter on it. The guys at Big Gun said there is no need to rejet but i know there is hidden power waiting to be unleached. I have done the free mods on it except for the YZ timing and this gray wire thing. I have all stock carb jets but i moved the clip position one slot(richer). At WOT my bike cuts out like its hiting a rev limiter or runing out of gas. I was wondering what jeting and/or needle i should run with my pipe and the gray wire cut. Please help a fellow 4 stoker out to spank all 2 stokes out there.

Any advice is welcome

Thank you


There is a whole new bike just waiting for you. On the 250F forum, there is a CDI 101 post that describes what the CDI and grey wire do. There are numerous posts on how to find it and cut it. This is going to be good for you.

The jetting is going to be even better. The cutting out and running out of gas symptom you have is because it is too rich. In fact, it is too rich everywhere. You can get by dropping to a main in the 165 168 range and lowering your needle two or three positions (1 or 2 from stock). It will still tend to foul with the original pilot. The real deal is a needle change. Taffy will probably chime in here, he's the guy you really need. I use a FHN needle, he and JD used to recommend a DMM or EMM needle but they tended to run close to the lowest clip position, so Taffy recently revised just the clip position part of it. Doing that will require an even smaller main jet. Don't be afraid, this is the key to power. It won't cost $40 bucks for the needle and a couple of jets.

The YZ cam timing changes the power considerably, mainly moving it from the bottom to the midrange. Up to you on that one. I've had both twice and don't really have a preference.

Good luck,


Thanks for the advice Mark. I found the grey wire and I took it around my street It seemed faster at top but I haven't got a chance to really ride it I have to wait till sunday.

About the jeting thing I read some were that the pipe would make the motor use more air and I thought more air more fuel so thats why I made it richer. Ill try your advice still and see how it gose. Thanks again for the advice :)


Yeah, the open pipe needs more fuel. Taffy touts a change of 10 in the jet number for an open pipe. But they are already rich on the top and choked down in the middle. Try the current Taffy recommendation for a needle (was EMM which still works but new one involves more central clip position) with a small pilot and small main jet.

Good luck,



keep reading. there are plenty of posts on everything here.

your stutter is because the needle is too high so drop it one position.

as MC says the MJ you want with that pipe would be about 162 and an E needle. if you go with the D needle go to a 168MJ

i would do the MJ first. this will lean off the juice where the needle works and you may not need to move it after the change.



You did not mention if you removed air box lid and throttle stop.. YZ timing= Releasing the Hounds!

Check in history there is about weeks worth of reading, then if you have any troubles, your fellow thumper's will guide you through it...


I would be a fool not to cut the throttle stop and the air box lit these things gave me some hp but I am in need of more power. Thanks for the jetting #'s I'll go to my local dealer today and pick up so jets and needles. Thanks for all you guys help on the matter. I will keep you posted on the out come. Also I hope to do the YZ timing as soon as I have time. I was also wondering if the YZ timing would make me run different jeting

Thanks again

you know just

your're the first person ever to ask that question :):D


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