Weak ignition???

8 replies to this topic
  • TallBoysWRF

Posted April 18, 2004 - 11:42 AM


I keep fouling plugs and I've pulled out a few plugs that did not look fouled, but do not spark when I test them. Then today I could not get a new plug to show sings of sparking. However when I check the plug with the bike in the gagage (darker) I can see a faint blue spark, but it's really tiny. If I wheel the bike outside (even though it's really cloudy) I can't see the spark. My experience tells me that I sould be able to see a nice healthy fat spark, Is this true for WR's? Is it possible that the ingition is getting weak? I put a new plug in the bike and it runs great, until the plug fails. Any advise?

  • dominator426

Posted April 18, 2004 - 12:03 PM


Maybe your spark plug cap and/or wire has deteriorated and resistance is too high.

  • TallBoysWRF

Posted April 18, 2004 - 12:10 PM


Is there an easy way to test it?

  • Hamish

Posted April 18, 2004 - 02:15 PM


go to Motomans site and download the workshop manual. Chaper 6 is where all the elctrical test procedures are.


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  • TallBoysWRF

Posted April 18, 2004 - 03:03 PM


go to Motomans site and download the workshop manual. Chaper 6 is where all the elctrical test procedures are.


Where is it at? I couldn't find anything in the downloads or Technical articles sections.

  • Hamish

Posted April 18, 2004 - 06:05 PM


click 'Tech Articles' then scroll down to 'Misc'
Or just click here


  • TallBoysWRF

Posted April 19, 2004 - 06:25 AM


Thanks, I'll check it out tonight. :)

  • madbajan

Posted May 23, 2004 - 08:54 AM


I'm suffering from the same symptoms as you are,did you find the trouble and if so what was it??

  • Mike_Desrochers

Posted May 25, 2004 - 02:01 PM


Did you have any luck with your ignition problem? Ive had similar issues regarding blown plugs in my 2002 WR426. The last time I rode all day, then the next morning we started out and then everything went dead. It did not seem like a plug problem it appeared to be weak spark. I was able to get it back to the truck and then proceeded to tear apart the carb thinking dirt may have been my problem, but no luck. Took it to my local Yamaha dealer, they started it and had the same problem. They checked the electrical system, spark and advised there was no problem. Then they cleaned the carb and it runs fine for now. Guess I will find out on the next ride.

Mike D.
2002 WR426


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