Fouled Plugs II

9 replies to this topic
  • Guest_Guest_*

Posted January 07, 2001 - 03:01 PM


Oh Geez...
After having a 00426 that had all the problems, (clutch basket, 4th gear, leaky tanks, etc...) Now I hear there is this problem with the plugs fouling.

I have not had any problems to this point... I have about 3 to 4 hours on the bike, mostly easy riding breaking it in.

When does this problem start to rear its ugly head.


  • Taffy

Posted January 07, 2001 - 03:40 PM


the moment you think you're so f******* clever you think you can improve on a $1m yamaha R & D budget on thirty bob! leave it alone.



  • Matt406

Posted January 07, 2001 - 05:46 PM


If your jetting is corret, you won't foul plugs on a regular basis. Check the jetting for your location and altitude. Make any neccesary chnges and everything will be fine. (Your bike will run stronger than ever, too!)


  • blbainb

Posted January 07, 2001 - 07:37 PM


The fouling problem seems to be only on some '01 426s. My '00 was jetted perfectly and never fouled a plug. My '01, OTOH has had the now classic fouling problem from day one. Jetting makes no difference (C'mon guys! You think we wouldn't try that?)

  • Moto-Mike

Posted January 08, 2001 - 09:15 AM


Exactly - I agree with blbainb.

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  • mikeolichney

Posted January 08, 2001 - 10:54 PM


Perfect agreement here. Problem from day one, the colder temps aggravate it. Near 50 degrees I have no problems (altough plugs are still black). Jetting does not help. My 99 had one plug change in 2 years under the exact same usage.

  • motoman393

Posted January 08, 2001 - 01:28 PM


Hey I got a solution for all your plug fouling needs.................move to Texas where it aint cold :) Just kidding anyway I hope Yamaha addresses this problem and fixes it free of charge for the defective bikes!


I get my kicks on a 2001' YZ426!
Friendswood, TX

  • Guest_Guest_*

Posted January 08, 2001 - 04:09 PM


I have been using the NGK CR8EK a twin electrode plug with good results. 45 Pilot and one clip richer on needle. 1 3/4 fuel screw. Other suggestion would be to make sure all paint is remove from under ground leads. In WI. so temp is around 20deg. and mine is running fine now. Hope this helps.

  • Guest_Guest_*

Posted January 09, 2001 - 06:55 PM


Hey Guys,
I appreciate all the insight. I will keep you posted on how mine runs next ride.

  • FreestyleThump69

Posted January 17, 2001 - 05:22 PM


Dear 2000 426 users
My name is devin Beard and when i got my 426 it had a CR7E plug in it. i have gone through some plugs experimenting but i have found the CR7E plug fouls the least because it runs hotter and seemes to start better and perform better than the CR8E and the CR8EK.

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