2010 YZ450 Spark Plug Question

6 replies to this topic
  • txjeffro301

Posted February 24, 2011 - 06:39 PM


Pretty simple question I suppose for some of you guys but here it goes...

I have been a 2 stroker for 30+ years and went ahead and bought a new 2010 YZ450. With the EFI and 4 stroke motors these days what are your thoughts on the CR8EIX Iridium plug verses the stock CR8E.

I use to run Iriduim plugs in all my 2 stokes but I would adjust the mix/jetting for what pipe I was running, alltitude ect... until I had it burning a nice golden brown and never scattered a top end...ever.

Is the burn that much different or hotter for a 4 stroke or this bike?
Does this matter?
Your thoughts and expertise is appricated.

The bike is stock, programmer and Yoshimura C4 full system ordered today.

  • MXR176

Posted February 24, 2011 - 06:59 PM


Its all I run in mine, and its all I ran in my YZ250 Smoker.... Got this from the NGK website.

Iridium is a precious metal that is 6 times harder and 8 times stronger than platinum, it has a 1,200°(F) higher melting point than platinum and conducts electricity better. This makes it possible to create the finest wire center electrode ever. Prior till now, NGK has favored platinum for their long life or performance spark plugs due to its high melting point. However platinum alone is no longer enough, ultra long life spark plugs and smaller center electrodes required harder and stronger precious metals. The strength, hardness and high melting point of iridium makes it very well suited for a fine wire plug and for ultra long life spark plugs. Though better, iridium's not perfect, it is very expensive, and at higher temperatures it oxides, thus rendering pure iridium as an expensively poor choice for spark plug construction. However when blended with other precious metals such as Yttria, Rhodium or Platinum, you can enhance those metals advantages with the superior strength and hardness of Iridium. DO NOT BE FOOLED, all iridium plugs are not the same. Iridium content varies, some other brands of iridium plugs are priced lower, (usually due to lower iridium content). They likely will not perform or last as long as a genuine NGK iridium spark plug.

  • grayracer513

Posted February 24, 2011 - 08:15 PM


Iridium plugs produce a reliable spark with less ignition energy, and last longer. There is no performance gain except that they will resist misfiring for a longer period, but the bike will start more reliably.

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  • brentn

Posted February 24, 2011 - 08:19 PM


Can you foul a plug on a four stroke? Carbon build up?

I was at a dealership when a guy behind the counter talked me into an iridium plug, said they last much longer than standard plugs and reduce fouling. I bought it and when I was in the truck I realized I don't have a two stroke anymore, and was also wondering how exactly the plug degrades over time when the engine is running properly?
Either way I put it in the bike, have 20 hours on it. Any interval that these should be replaced?

  • grayracer513

Posted February 24, 2011 - 08:26 PM


Yes, four stroke plugs can foul. The insulator can accumulate a conductive layer of deposits, or the carbon can become temporarily soaked with fuel and be conductive until it dries out.

  • txjeffro301

Posted February 25, 2011 - 10:30 AM


Well, thats for all the input guys and from what I can see the iruidum plug should be no problem. I will keep checking this for newer updates.
thanks again.

  • 12bruckd

Posted February 26, 2011 - 06:40 AM


whenever i foul a plug in my two stroke i just take a wire brush and very carefully brush off all of the carbon and the bike fires right up, probably the same for a four stroke.

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