Grey wire?

What do you guys mean by "no grey wire"?

THere is a gray wire leading into a wiring harness under the gas that goes to the ignition module on US models. This wire somehow controls the midrange to make the bike quieter, so it can pass sound tests, at the expense of midrange power. By pulling the gray wire out of the connector, it is possible to gain a midrange boost, which is quite noticable. Do search on it, and I'll bet you could learn more, and even how to do it.

Thanks for the info!!!!!!!


Where do you ride dude? I'm in the 'hood as well. We have a good group of guys that ride weekly...well, they ride weekly, I try to ride weekly. Just got my WR a few weeks ago. Man, what rocket this thing is once unplugged!

CUT HERE......


Roost on....

Bonzai grin.gif

YAMAKAZE, is the grey wire next to the yellow wire in your photo?

Yes. That is the correct wire. Consider pulling the wire out of the connector rather than cutting it. It is replaceable like that. It is a little harder, but you can change in back.

This applies to 99 WR also?

The Yellow wire is NOT part of the 2 wire bundle, it just looks like it. The bundle is the Black wire with the white stripe and the gray wire. Cut the gray one. Some people push the pin out of the connector, I just cut it and placed a terminator on the cut ends to protect them and prevent a short.

This is a 99 WR400F, The wiring harness is the same throughout the different models.

Bonzai grin.gif

Thanks guys, can't be anymore simple than that.

After cutting the Grey wire, is there a need to make any jetting changes?


No jetting required!! smile.gif


'99 WZ/YR (you choose!) with ALL YZ mods, de-octopused, DSP Doug Henry airbox w/ velocity stack, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, OEM YZ tank, IMS YZ seat, Mobil 1 15W-50.

Howdy could I put a toggle switch on it to turn the extra power on and off while riding? And would it be safe fo the engine to do this.???Thanks JIM wr426- 01


You could easily splice in a toggle switch, many did when this MOD was first discussed due to fear that it would screw something up. I think most of them have removed the switches. It won't hurt the MAP but I don't think that I would advise operating the switch while the motor is running. Electrical spikes and surges are never good in any circumstance.

Bonzai grin.gif


1999 WR 400F:

Headlight Removed,Odo Removed,Gray Wire - Cut,Throttle Stop - Trimmed,YZ Timing,GYT-R Pro-Bend Hand Guards /Tripple Clamp Mounts,YZ Front/Rear Fender,YZ Number Plate,Race Tech Suspension(by MXTuner),Dunlop 756 Front and Rear,Renthal Fat Bars W/GYT-R Pad,Renthal 14/53 Gearing,DID Race Chain,Custom Grips,Graphics by CEET,White Brothers E-Series Exhaust,Modified Compression Release,Acerbis Frame Guards,12 oz Flywheel Weight;Polaris 400 Sport,Polaris 250 Trailblazer

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