Gray wire mod

3 replies to this topic
  • yamwr426

Posted May 18, 2004 - 11:26 AM


I am new to TT and find it very interesting. I have an 01 Yamaha WR 426 that runs and rides perfectly. The throttle stop has been cut and the air box lid removed. I would like to know if I can unplug the gray wire without advancing the cam timing. Would it do any good or cause harm? I am not ready to give up reliability for speed, however if it will help, I am all for a little more. Any advise would be most appreciated. Thanks.

  • Fastest1

Posted May 18, 2004 - 03:00 PM


Yes you can do it without doing anything else. It is a neutral rev limiter. You can disconnect the TPS by unplugging it too. Dont ever cut the wires just remove them from the plug and tape them up. You can always go back easily that way.

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  • wrooster

Posted May 18, 2004 - 04:43 PM


Any advise would be most appreciated. Thanks.

while not specifically written for the 426/450F's, the 250F FAQ will answer a lot of your questions regarding your new bike. there are details on the grey wire, greasing, jetting, and a million other things. see the link in my sig.

jim aka the wrooster
'01 wr250f

  • Rick_Kienle

Posted May 18, 2004 - 06:52 PM


It is a neutral rev limiter.

Actually the gray wire is a ground for the CDI which switches the timing map to the "WR" map. Disconnecting it forces the CDI to use the "YZ" map.

THe sky blue wire is the neutral switch wire which lowers the rev limiter RPMS and decreases spark while in neutral.

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