new member; two question

7 replies to this topic
  • Andrea

Posted February 08, 2004 - 07:28 AM


hi to all I am an Italian boy and I had two questions to set to the forum;
the to remove the blue wire and the neutral switch which advantages handed? il dsp powernow is true that it increases the horsepower to the low regimes?


  • yamaha.dude

Posted February 08, 2004 - 10:00 AM


The PowerNow, or homemade JamesNow! will increase the pickup and response from the bottom end of the powerband... it is hard to quantify the actual HP or torque figures, it is more of a 'seat-of-the-pants' thing... :)

The blue wire basically is there to prevent you from over revving the bike in neutral, and I believe it also modifies the ignition timing somewhat in order to make the bike start a bit easier...

Good luck,


  • yamaharichey

Posted February 08, 2004 - 12:53 PM


You sure he's not talking about the grey wire?
And by the way welcome italian boy, I thought you guys only rode Huskys.

  • Indy_WR450

Posted February 08, 2004 - 01:15 PM


No he is talking blue neutral switch wire and the awesome Power Now! :)

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  • tcmII

Posted February 08, 2004 - 04:18 PM


Ok, I just did all of the research for my 1998 WR400. Based on the Yamaha manual and the thumperfaq site, here is the the wiring answer:

Light blue wire from switch reduces spark and lowers rev limiter rpm when in neutral. While it may be a multi-pin connector, you can just disconnect the connector. Hotter spark for starting and higher rev limiter prm.

Grey wire gets low volt signal at start-up to select spark mapping. Grey wire connected WR map, grey wire disconnected YZ mapping.

Note: the grey disconnect will not offer much improvement without the throttle stop modification. The mapping differences are past the WR throttle stop.

You can research all this and other "free mods and upgrades at thumperfaq .

Hope this helps with the wiring.

  • Andrea

Posted February 11, 2004 - 07:19 AM


thanks for all the answers, do I have a last question, the grey wire there is alone on the motorbikes USA? correct?


  • Indy_WR450

Posted February 11, 2004 - 01:13 PM


Yes. Only the US models have EPA gray wires. :)

  • yamaha.dude

Posted February 11, 2004 - 07:10 PM


Here is a pretty good thread from the 250 side... applies just the same to the 4xx bikes I believe...





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