Spark plug difference on 426

6 replies to this topic
  • beasleys

Posted August 29, 2005 - 07:51 AM


I replaced my spark plug for the first time since I have owned the bike this weekend. I got a new plug from the dealer and it was a NGK CR9E. There was no problem with my old plug just some preventative maint. Well i pulled the old plug out and it was a NGK CR7E. What is the difference if any between the 2 plugs? I used the 9E from the dealer and worked fine, just wondering for future reference. Thanks :D

  • DaveJ

Posted August 29, 2005 - 09:16 AM


The number represent a heat range, which is determined by the exposure of the ceramic cone.

Additionally, I would stick with the factory heat range unless you have a reason to run colder or hotter. And, the EK plugs (double electrodes) are better than the standard Es.



Posted August 29, 2005 - 04:07 PM


the CR7E is a hotter plug. the lower the heat range number, the hotter the plug runs.

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  • Slowmotion426

Posted August 29, 2005 - 08:29 PM


The NGK CR8E is what the manual calls for on my '01 YZ426F.

  • Ryan426

Posted August 14, 2010 - 06:27 PM


Sorry to open an old thread but I have a ? Hope some one can help me. My '01 426 now has a CR9E and I have a new CR8EK. My question is what does the K mean. The manual says to use CR8E.

  • grayracer513

Posted August 15, 2010 - 07:12 AM


The K indicates it is an iridium spark plug. It's the same heat range as the CR8E, but with the improvement of a precious metal electrode. The plug is less prone to fail to fire due to partial fouling, and will make the bike start more reliably. It should also last a lot longer. Perfect for your bike.

  • Ryan426

Posted August 15, 2010 - 09:13 AM


Thanks gray for the reply.

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