Grey Wire

26 replies to this topic
  • yamahaxt

Posted May 11, 2006 - 03:03 AM


Any pictures of the Grey Wire on the WR450 2006? So I can disconnect it.

  • yamahaxt

Posted May 11, 2006 - 05:04 AM


If nobody has an pictures then where is it?

  • bcs

Posted May 11, 2006 - 05:23 AM


Here is a pic of my 2006 WR450. This is shown with the gas tank removed, left side of bike.
The large, 6-pin connector in the center is the one. You can see that I pulled the pin back out of the connector (didn't cut anything) and folded the wire back into the black plastic sleeve around the wire harness. No need to insulate it or anything, it just goes to ground anyway. If you do it this way, it can always be restored to the stock configuration. Not sure why anyone would, though.
You'll see that the space on the connector is now filled with a bit of black silicone for waterproofing.


  • yamahaxt

Posted May 11, 2006 - 06:13 AM


Thank you for the picture.

  • wr400rider

Posted May 11, 2006 - 06:39 AM


what does disconecting this grey wire do? and do i have one on my 2000 wr400?

  • rooster wrooster

Posted May 11, 2006 - 07:58 AM


The US WR250F comes with the gray wire from the CDI connected to ground. All the other 250Fs have this wire disconnected. There are two different maps (spreadsheets) in the WR/YZ bikes. One is for the YZ and is selected if the gray wire isn't grounded. The other is for the WR and is selected if the gray wire is grounded. With the gray wire connected an alternate ignition-timing map is used. The �WRF� map retards the timing at the mid and upper RPM so that the bike will run with the stock baffle and throttle limiter installed (see link with actual engine data analysis by TT member McGrath). If you remove the baffle and alter the throttle stop you should also remove the grey wire. Most people do not like the alternate mapping and disconnect it, especially after doing the other free mods. Initially it was advocated to cut the wire, and many riders have. There are disadvantages to cutting the wire. First if you may initially cut the wrong wire. Second, if you decide at a later time to return to the original ignition-timing map it is more difficult. Most now advocate simply disconnecting the wire from the connector and taping it off with electrical tape. For more information about this topic see CDI 101 or the Grey Wire thread in the ThumperTalk archives.

By the way yamahaxt, was that you last saturday out at the mounds hitting those doubles? I allready thought your bike was modded from the way you were riding!

  • KiwiRacer

Posted May 11, 2006 - 06:36 PM


On the WR250F the grey wire mod is the way to go, But on the 450 its not that necessary to do it, If your riding real hilly ground then you want smooth power from the 450 keep it connected, If riding open fast ground then the mod isn't needed at all cause your on the pipe more.The mod only effects the power down low after half throttle the mod does nothing.

  • dsalvetti

Posted May 11, 2006 - 08:24 PM


Hey guys!

My understanding was that the "grey wire" was put in to retard the timing through the mid-range to help the bike run better with the half-throttle stop and to help with emmissions. If that's true, wouldn't disconnecting it help the mid-range performance once you start running a YZ-spec throttle stop?

I'm new to this whole dirtbike world and absolutely LOVE my WR450! I have about 7 hours on the bike and just picked up the AIS Removal Kit from my dealer. I think I want to install a switch with my grey-wire mod... just the way I am.

I can't wait to see how much difference there really is!


BTW, thanks for all of the great info on this forum! :ride:

  • bcs

Posted May 11, 2006 - 09:31 PM


It has been reported here that if you installed a switch, you can't switch back and forth; the logic in the ignition is based on the circuit at the time the motor is started. (you might want to do a search and get the full version of the story).

  • odonnks

Posted May 12, 2006 - 01:57 AM


As I understand it, the ignition timing map is selected once the CDI is booted up. (Pressing the power button). After that to reselect the timing map the bike would need turned off and powered down, flip your switch and restart.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • yamahaxt

Posted May 12, 2006 - 03:08 AM


So do disconnect it or leave it on. I cut my throttle stop to yz specs and repmoved the insert on the exaust. I was going to cut the grey wire tonight. Good or bad ideal?

  • yamahaxt

Posted May 12, 2006 - 03:11 AM


Bad typing on that last post. sorry for the incorrect spelling.

  • Just_a_trail_rider

Posted May 12, 2006 - 05:17 AM


I re-connected my gray wire to see if it would make a big difference. It was more mellow up top for sure, but still fast enough for the type of riding that I do.

I've never been the "rip it up" type of rider. I am mostly enjoying the view. So I don't really need to go 90mph. That isn't much fun for me. I tend to prefer single track trails through the desert. I'm not going that fast.

If I were riding in other areas, it might be different. I can see the need to have a grey wire switch.

I still have my pipe and jets installed, so I am sure I am getting much more power than stock, especially off idle where the grey wire doesn't matter.

I did notice how smoothly I went up hills. The bike has the torque and I didn't worry so much about throttle/clutch mistakes.

Cutting the grey wire is a preference I guess.

  • OneToGo

Posted May 12, 2006 - 10:10 PM


Rooster has the right slant IMO.
Push the wire out and block the hole with sealant, like in the pic someone (sorry) provided. The looms on the 06 are on the right side but the grey wire is in the middle of the clear plug, same position.
Definitely more of a hit from Mid to high RPM - anyone for clearing doubles?
Yes, the gray wire is an earth that is read at CDI power up (switch on) and connot be switched "on the go". To have a "dual" curve readily available you have to go to an aftermarket system such as Vortex. Now, they have some really smooth :ride: selectable curves as well as FULL POWER :banana: mode at the flick of a switch. Specially made for YZs and WRs too...

  • odonnks

Posted May 13, 2006 - 02:12 AM


As One said, slide the wire from the connector.

  • OneToGo

Posted May 13, 2006 - 10:45 PM


Any pictures of the Grey Wire on the WR450 2006? So I can disconnect it.

See here:

06 450F CDI with Grey Wire disconnected:


P.S. No need to remove CDI! I had mine off for other reasons.

1. Pull apart connectors (grey wire is in centre of clear one)
2. Push on wire PIN with flat blade screw driver OR depress inside retaining clip and gently pull wire - it will pop out
3. Seal with silicone - mine is white in pic.
4. Tape or shrink wrap the exposed Grey Wire (mine is shown bare)
5. Re-fasten plugs and reassemble bike

PRESTO - grey wire Mod


  • carlicarli

Posted June 01, 2006 - 09:13 AM


dirt bike magazine had a picture of the grey wire.
I am looking for a picture of the grey wire for my WR426 01.


  • pattch

Posted June 02, 2006 - 01:18 PM


^^^^^^Same Here! :applause:

  • byggd

Posted June 02, 2006 - 02:27 PM


Any pictures of the Grey Wire on the WR450 2006? So I can disconnect it.

Does this help :applause:

  • modguy

Posted July 06, 2006 - 01:30 PM


my 1999 wr 400 doesn't have a gray wire, i don't understand all the wires look like they go to something other then being just grounded or anything


Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.