Will Grey wire really help

27 replies to this topic

Posted July 01, 2002 - 05:58 AM


Where is the magic gray wire located?

  • tk421

Posted July 01, 2002 - 07:41 AM


I think the grey wire can be accessed by a black connector under the tank on the shifter side of the bike.

July’s issue of Dirt Bike mentions the grey wire. They say: “Remove the grey wire and tape up both ends for more bark”
Excellent bit of hearsay. :)

[ July 01, 2002: Message edited by: tk421 ]

  • Red-eyed_Demon

Posted July 01, 2002 - 08:13 PM


Actually, the black two wire connector is on the "brake lever" side of the bike just underneath the gas tank. I was able to pull the wire out of the conector towards the front of the bike with some needlenose pliers, so I didn't have to cut it. I just put some shrink wrap and electrical tape over everything, and can put it back like it was if needed.

  • tk421

Posted July 02, 2002 - 10:02 AM


The complete grey wire quote from Dirt Bike is as follows:
“This grey wire de-tunes the ignition for noise regulation. Disconnect it and tape up the ends for better bark.” Dirt Bike Off Road Special Test. 2002 July Dirt Bike.
Noise regulation? Hmmm. Isn’t combustion combustion? What difference does a spark have on the noise that follows combustion? It would have to ignite less fuel to have a quieter explosion so to speak. If that were so, removing the grey wire simply advances the timing, right?
Just a thought.

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  • tk421

Posted July 02, 2002 - 01:08 PM


Thinking out loud here. :)
Re-mapping/advance timing I suppose would be a little far fetched for one wire to change. It would be like starting a subroutine or something. I don’t think YAMAHA would spend money to engineer such a feature in there CDI. Plus there would be cases of people having an engine that pings a lot after disconnecting the grey wire due to the timing advance.
Would it then be safe to assume the grey wire is a “spark suppressor”? At a certain point the CDI would just LOWER the spark intensity to not completely “burn up” the fuel mixture? (keep down the noise) This to me would be easier and less expensive for YAMAHA to get around the sound regulations, and maybe why they don't talk about it?
If this is the case, a hot spark all the time is better I would think.

[ July 02, 2002: Message edited by: tk421 ]

[ July 02, 2002: Message edited by: tk421 ]

  • tk421

Posted July 08, 2002 - 02:37 PM


mlc flooring

For what its worth:
I disconnected my grey wire before riding this weekend. Did not notice any performance gain. Mid range engine control seemed more stable. The bike ran perfect all weekend. Outside air temperature was 95 degrees. No engine pinging at all. I did completely change the gas before riding, no additives.

  • Steve_WR400F_#61t

Posted July 08, 2002 - 07:15 PM


I did the grey wire mod & noticed a difference on my 1st ride. There's not a big difference in overall power, just got rid of the midrange surge of power. I think it pulls a bit harder earlier and continues all the way through the midrange & into the top. Then I did the YZ timing & got a bit more performance out of the bike. This opens up the bike a bit & lets it rev a little quicker. Basically, the timing on a stock WR is retarted, both in valves and ignition. The grey wire advances the spark timing and the YZ timing opens up the exhaust valves one tooth earlier. The combination of the two lets the bike breath better, rev quicker, and just bring out a but more performance. Nothing huge, just small steps in the right direction.

  • Ga426owner

Posted July 09, 2002 - 04:15 AM


TK, the grey wire mod came from a insider at Yamaha. It works real well on a 01 WR as I have tested on mine several times. I am not sure about a 02, as the mapping may have been altered.


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