I did the blue wire mod, Now it won't start!

12 replies to this topic
  • Zugg Zugg

Posted November 26, 2005 - 02:24 PM


I did the blue wire mod after riding last weekend. Now the MF won't start. I did get it to start by pulling behind another bike, Once I put the blue wire back where it belongs. But it acts like it is getting too much fuel and won't stay running. It is an 02 yz426f. No mods. I'm ready to torch the no running SOB and get an f'n crf450X with the "magic button"!!

  • ripntear

Posted November 26, 2005 - 02:37 PM


A yz326f? There's the problem!

You lost 100 cc's.

I bet if you find them it'll start

  • djbiker

Posted November 26, 2005 - 04:28 PM


i would never suggest doing any thing to the stock computer the reason why its acting funny is because when you tried to start it it probity got flooded and needs to sit over night. my best guess would be to get a high performance CID from pro curit

  • WR450F_RDR

Posted November 26, 2005 - 05:35 PM


is it a "blue" wire mod on the yz426 or is it like the 450 a "grey" wire mod. Maybe you unplugged the wrong wire??

  • SXP

Posted November 26, 2005 - 06:09 PM


I did the blue wire mod after riding last weekend"!!

Right there is your problem - it's the grey wire mod! :applause:

  • yogist

Posted November 27, 2005 - 07:21 AM


I pulled the blue wire from the plug and did the bk mod as described at Motomans 393 website..Bike is so reliable..Fires all the time runs great.. :applause:

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

Posted November 27, 2005 - 07:32 AM


So I guess that means it is fixed now right?

  • sirthumpalot

Posted November 27, 2005 - 08:24 AM


Try a new spark plug if you haven't already. Your fiddling with wires is the most likely cause, but the symptoms sound similar to a wet spark plug.

  • Satch0922

Posted November 27, 2005 - 08:32 AM


the blue wire mod works...it is not your problem. SirThump is right....change the plug. You were obviously having starting issues that provoked you to try the blue wire mod? Maybe jetting is off and it's too rich?

Heck I completely removed my neutral switch and wiring harness from my 426 and replaced it with the RED Dr.D site glass!

Posted Image

  • Zugg Zugg

Posted November 27, 2005 - 09:46 AM


Yes, it definately is an 02 yz426f....sorry for the typo. Grey wire mod??? Isn't that for 450's?

Anyway, once the blue wire was re-installed it would only start when pulled by another bike. Kickstarting was out of the question. When I returned home, I pulled the plastics, tank, and checked the plug. Damn plug was soaked! I have bought a new plug and will install it today. The bike ran great the last time out, it has always started (cold) with a kick two. When hot, it has never been easy to start. Yesterday it totally sucked!! Is there any explanation for why it won't start with the blue wire mod being done to it? I wonder if maybe the float is stuck (i.e. carb problem) or something like that.

  • sirthumpalot

Posted November 27, 2005 - 03:48 PM


When it's hot, are you using the hot-start? The hot-start is a must for most hot 4-stroke MX bikes. And do not.. DO NOT twist the throttle while you kick. If you're a 2-stroke convert and have the involuntary habbit of twisting while you kick then try grabbing the bar inside of the throttle, or grab the brake resevoir, etc..

  • shanedut

Posted November 27, 2005 - 06:13 PM


It sounds like a jetting problem to me. If it wont start when hot with the hot start there is a jetting issue or a carb issue. I would clean the carb out and change the spark plug. Make sure when you clean the carb out that both your hot start and choke are not plugged up and that they work properly. Make sure you removed the light blue wire not the dark one. I did the blue wire mod on my 426 and it worked fine.

  • Zugg Zugg

Posted November 28, 2005 - 06:54 AM


Grabbing the brake reservoir works best. It most definately was the light blue wire. I never kept it running long enough to use the hot start. However, it has been effective in the past. I guess I'll pull the carb and check it over. Thanks.

Related Content

WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

yz400f throttle bog by yz400fmaniac

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • * * * * *
  • Hot  28 replies

Need help by Goforaride

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  68 replies

2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

Is the 2016 GYTR Yamaha YZ450F too fast? by Fryboy

Dirt Bike   Special Interest Forums   Pro Racing
  • * - - - -
  • Hot  241 replies

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.