possible fouling fix

59 replies to this topic
  • Ramrod

Posted March 24, 2002 - 12:45 PM


By the way, what does disconnecting the grey wire do for WR's?

  • thumper4life

Posted March 24, 2002 - 03:06 PM


im interested in disconnectin the wire, but im a motocrosser and i miss some shifts occasionaly. if i miss a shift and hit a neutral, will this wire bump the limiter up to the "in gear" limiter?

  • teamtoxic

Posted March 24, 2002 - 03:20 PM


This weekend I was discussing this mod with a friend of mine. He says that after disconnecting the light-blue wire, the spark WAS more intense than when it was connected.

Another thing, since nobody seems exactly sure on the wire's purpose, why not use a small switch rather than just cutting the wire? You would simply flip the switch off for cold-starting then flip it back on when it's running. This might add one more step to the starting process (when cold) but I don't think it would be necessary to use it once it's warm. I know I have no problems starting my 426 when its hot.

It's about time to put the sleds away and pull out the bikes so I'll definately add this mod to my pre-season maintenance list.


  • motoman393

Posted March 24, 2002 - 03:42 PM


You dont cut the wire...you just pull it out of the harness w/needle nose pliers! You can even do this w/o taking off the gas tank (just take the right shroud off). This mod is NOT permanent, you can plug it back in at any time! Later,


  • 2_SMOKE

Posted March 24, 2002 - 05:05 PM


Have you guys heard about the air in your tires I heard if you run 50lbs it feels 20lbs lighter? :)

  • vmprz515

Posted March 24, 2002 - 06:31 PM


hey guys
garrett(motoman393)and i mostly garrett, pulled the blue wire from the harness and taped it up. we then tried to start it and it fired up on the first kick. i am very happy with this so far, though i have not been able to ride since the mod. my bike fouls almost every time i go ride and i always have trouble starting it, so maybe this is the answer to my prayers. thanks alot.

  • Yz426King

Posted March 25, 2002 - 07:04 AM


I did the mod to mine, just unplugged the neutral switch harness. I was riding yesterday, it was about 80F here is southern indiana. After I had been riding for a while I intentionally stalled it and tried to start it without the hotstart, it fired up beautifully on the first kick.

  • teamtoxic

Posted March 25, 2002 - 01:05 PM


what I was suggesting was that rather than leaving it unplugged all the time, an added switch (at an easily accessible location)would allow you to "unplug" it whenever you want, with just the flip of the switch. Flipping a well-positioned switch is much faster than removing the shroud to get to the wire.

No one is sure what EXACTLY this does for the ignition system so it may be better to leave it connected while riding and only disconnect it when starting. If the timing IS altered by unplugging this wire, you may end up losing power even though you might not notice it. Nobody wants that! Besides losing power, there are also other downfalls to timing changes that I won't get into.

Just my 2cents
Ride Hard

[ March 25, 2002: Message edited by: teamtoxic ]

  • John_Lorenz

Posted March 25, 2002 - 01:08 PM


:) Take a look at the April MXA, it shows Tim Ferry's 426. it also explains he is using a stock but modified Carb. Look at the Pic that has no sensor on the crab in fact it is blocked off. Real good article. Intersting Exhaust pressure cooker attached also

I think the Sensor is nothing more then EPA Crap

Thoughts :D

  • Danny_Seydel

Posted March 25, 2002 - 02:09 PM


3rd day in a row (with blue wire gone) 1st kick every time, and were talking Washington weather. this is great!!!A WHOLE NEW BIKE!! :)

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

Posted March 25, 2002 - 07:31 PM


Hey Norman / Motoman393 / TT members / Steve & Bryan:

Thank You... Thank You... Thank You... Thank You!!!!

Last year, after I test rode a YZ-426 for the first time, I knew I had to have one. Bought my 01 426 in late Dec. Up till then I've owned only 2-smokes (not a confession---just a fact). Between then and now I found out about TT, I've learned more about how to improve, fix, perform preventive maint., modify, repair, clean, ect. ect. my blue beast. Now I can add a new item to the list of improvements to the best bike I've ever had. (Please Note The (light blue wire) On My Signature). Hats off to all of you at TT, keep up the good work guys.

Boyd :) :D

  • thumperman

Posted March 25, 2002 - 09:17 PM


Interesting post. Just in case any of you were wondering if the problem was you or the bike, I have had my 02 426 since 3/00. I originally had some problems starting and was wondering if I bought the wrong bike. Since then, I religously follow the script and don't have any problems starting. I have the ORIGINAL plug and never had any fpouling problems. The drill is 4 or 5 kicks with the compression release in, then let it off, then pull it in and kick it down a little maybe one 1/4 of one stoke (about 10 degrees), then let it back up and let the release off. The hopegfully it kicks all the way and starts. if I miss the TDC, i do it all over but it starts. When i stall, use the hot start. Hot or cold i never give it gass before starting - never.

Now, for the blue wire topic, has any one found a reason to do this for an 2000? Did they change the electronics for 2001 and newer?

  • thumperman

Posted March 25, 2002 - 09:19 PM


Whoops. It is late . I meant I have had a 00 since 3/00 not a 02 since 3/00. That would have been interesting. Sorry.

  • Mud_Sweat_&_Gears

Posted April 04, 2002 - 09:55 AM


I'm with teamtoxic! Splice in a micro-switch to toggle the sky blue wire OFF/ON to improve starting and still retain neutral switch / CDI programming (whatever that may be). A win-win situation! :)

  • motoman393

Posted April 04, 2002 - 12:15 PM


where did you buy the toggle switch at (Radio Shack) how much? If I did the toggle switch route I would fab up a cool mounting spot for it, so everyone would ask "what is that?" Then I would reply: "oh that switch... that is only the Turbo switch, it just adds 50 more RWHP" :) This is another great post. Later,


  • PK

Posted April 05, 2002 - 11:24 AM


I know the original intention of the neutral switch was to limit engine rpm's in neutral so the bike could pass the European sound check test. I didn't that the spark was also reduced. Don't understand that one.

  • Uncle_Rich

Posted April 05, 2002 - 11:47 AM


I just unpluged the harness that connects the netural switch to the main harness.
Also I removed the netural switch and replaced it with a ZipTy Racing Blockoff Cover


  • teamtoxic

Posted April 06, 2002 - 11:25 AM


Garrett and all,

A nice toggle switch should run $2 - $3 at RadioShack. Once mine is on I'll tell everyone its my N<sub>2</sub>O switch. :)
As I type, I'm checkin out your site on the swingarm wear problem. I have my bike torn down to nothing but the frame and motor. I'm going through everything. I have some wear/pitting under my chain block as well. Gotta fix that.


  • yamie_rider

Posted April 07, 2002 - 03:01 PM


Originally posted by Danny Seydel:
3rd day in a row (with blue wire gone) 1st kick every time, and were talking Washington weather. this is great!!!A WHOLE NEW BIKE!! :)

Umm...This blue wire trick, is it for the YZ or WR.

  • john.hilton@cape.k12.de.u

Posted April 08, 2002 - 05:00 AM


Consider me another positive vote for the blue wire mod. My bike was a plug fouling fool this winter, it was truly getting on my last nerve.

I un-plugged the light blue wire this weekend (temp about 40 degrees) and the bike ran great. Started 1st kick after sitting for 4 weeks, started 1st kick all day, and purred like a kitten/tiger.


[ April 08, 2002: Message edited by: john.hilton@cape.k12.de.u ]

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