Updated Spark Plug Information

[MrClean731]

Just got off the phone with NGK. Wanted their input on going to an Iridium Plug on my 2015 FJ09. Here is what they advised.

Stock NGK Plug:  CPR9EA-9   Electrode Length 3.0mm

IX Series Iridium Plug: CR9EIX (Stock # 3521)  Electrode Length: 1.0mm

Laser Series Iridium Plug: CR9EIA-9 (Stock # 6289) Electrode Length 1.8mm  GAP: .035"

The shorter Electrode mean it takes a little longer for the plug to reach Operating Temperature. If doing mostly in town riding where you may be idling  a lot, might be better to stay with the stock plug. Otherwise the NGK Rep recommended the Laser Series.

For more info, here is the NGK link...

https://ngksparkplugs.com/en/products/ignition-parts/spark-plugs/platinum-spark-plugs

 

 

 

 

 

Edited January 13, 2022 by MrClean731

[skipperT]

While others may appreciate this information, I’ll remind you that Yamaha recommends standard plugs for a reason. There are NO benefits to running an iridium plug in the CP3 engine. 

More than one person has had intermittent running conditions and misfires under load that were ultimately traced back to iridium spark plugs. 

-Skip

[knyte]

7 minutes ago, skipperT said:

intermittent running conditions and misfires

I've had this occur in a 4-wheeler, too.  Same thing.  Replacing the iridium plugs back to standard sorted it out.  Some people swear by them, and I've had success with them as well as failures, but it seems to depend on the engine.

They're great if they do run reliably because you don't have to change them out nearly as often.

[kilo3]

Same here, always issues with iridium for some reason, especially turbo'd applications . Luckily most of the engines I ran into were easy swaps so I stick to plane jane copper and swap accordingly.

[roadrash83]

I just pulled two new NGK Iridium plugs out of unopened boxes for my XR1200 and one of the plugs screw on terminal nut was striped out and loose in the box. I kind of wonder if they where knock offs as I have never had a problem with NGK plugs. I think I bought them on Amazon a year or so ago, should have checked them before putting them in the parts shelf☹️

[whisperquiet]

My 900 GT has the original plugs with almost 19,000 miles on them and the bike runs great.  They will be replaced with OEM plugs when the valve clearances are checked around 24,000 miles along with the OEM Yamaha air filter.   I won’t fix anything that is working fine.

[texscottyd]

10 hours ago, skipperT said:

More than one person has had intermittent running conditions and misfires under load that were ultimately traced back to iridium spark plugs. 

I had heard this a few times, but always quietly suspected there was something else going on…  ‘better’ plugs couldn’t possibly be a problem, right?  😉

Then I put a set of iridium plugs (16 of the damn things) in my Ram truck, and immediately regretted it.  Noticeably rougher running under load, especially at low rpm open throttle, which is usually the sweet spot of torque delivery for the hemi.  After many curse words were spoken, I swapped in a set of standard copper core NGK plugs, and everything returned to normal. Lesson learned.   

[betoney]

1 hour ago, whisperquiet said:

They will be replaced with OEM plugs when the valve clearances are checked around 24,000 miles along with the OEM Yamaha air filter.   I won’t fix anything that is working fine.

Personally, I would check the air filter much sooner than 24k.  I have the GYTR Yamaha reusable filter and depending on the conditions I ride in, clean it several times a year.  Even if it isn't caked with dust, it is ALWAYS full of insects.

[2and3cylinders]

The term normally used instead of electrode length is "reach".  I tried both plugs with best success with the CR9EIA-9 mentioned but because its reach is so much shorter than oem, went back to the latter.

Now being anal and seeking some fun I "indexed" the spark plugs with indexing washers after determining which orientation the center electrode was least shrouded by the ground strap from intake swirl using a bore scope camera and trial and error plug reading. 

BTW, it's toward the intake valves, which is often the case; referred to as 6 o'clock.

[MrClean731]

On 1/13/2022 at 9:30 AM, MrClean731 said:

Just got off the phone with NGK. Wanted their input on going to an Iridium Plug on my 2015 FJ09. Here is what they advised.

Stock NGK Plug:  CPR9EA-9   Electrode Length 3.0mm

IX Series Iridium Plug: CR9EIX (Stock # 3521)  Electrode Length: 1.0mm

Laser Series Iridium Plug: CR9EIA-9 (Stock # 6289) Electrode Length 1.8mm  GAP: .035"

The shorter Electrode mean it takes a little longer for the plug to reach Operating Temperature. If doing mostly in town riding where you may be idling  a lot, might be better to stay with the stock plug. Otherwise the NGK Rep recommended the Laser Series.

For more info, here is the NGK link...

https://ngksparkplugs.com/en/products/ignition-parts/spark-plugs/platinum-spark-plugs

To add to this post, based upon some past comments, regarding misfires when Iridium plugs were tried...

While researching this, and making note of various NGK plug numbers used by Forum members, of the numbers referred, only one of those came up in discussion with the NGK CS Rep. That was the CR9EIX, with the shortest electrode versus the stock NGK Plug.. And the rep went on to recommend the Laser Series plug. So if those that complained of issues, could it have been related to an incorrect plug application? Just saying it could be a possibility.

If you definitely experience problems then going back to the OEM Plug would be the logical step.

My point here is to strictly provide info (as accurate as possible) and not dispute people who had bad results. 

 

 

 

 

 

[skipperT]

21 minutes ago, MrClean731 said:

 

Appreciate the info but that’s why I chimed in… because people HAVE had issues and I feel that one of the purposes of these forums is to provide accurate info and not just assume that something is ok to do because some guy at NGK looked at a computer screen and gave his opinion so that you’ll buy a more expensive spark plug and think it’s ok.

I’m not trying to get your back up, or provoke you with that comment, simply telling it like it is. As a rule, I also don’t post “anecdotal” info, but data that I can confirm because I’ve seen it on other motorcycles. (Just to explain where I’m coming from a bit further. ) How much hands-on experience does the guy at NGK have diagnosing ignition system problems on motorcycles?

as @2and3cylinders mentioned above, there is a difference in length.
 

This, plus the different composition and the fact that some ignition systems aren’t designed to provide spark to an iridium plug is why I don’t recommend anyone straying from the stock NGK spark plugs. It’s really just not worth the potential for problems. No one has blown ignition coils yet on these bikes yet due to improper spark plug replacement type or too long intervals, but the first gen FJ models are only 7 years old. Time will tell. 

-Skip

[skipperT]

2 minutes ago, skipperT said:

Appreciate the info but that’s why I

*snips*

2 minutes ago, skipperT said:

 

 

(Sorry, click the bolder NGK Iridium spark plug title above to see the pic I linked up)

[MrClean731]

So recent comments made me do some more research. Here is some more info in regards to the use of Iridium plugs...

per NGK engineers in regards to the use of fine wire in an Iridium plug, ...."because of its small size, can reduce the required coil voltage by as much as 20 percent. This means there an even greater reservoir of voltage at the coil if the cylinder requires it." 

Fine wire plugs were designed for modern high mileage engines, the addition of precious metals to the center electrode was to increase durability.

NGK goes on to state.... " The move to iridium plugs could potentially be a performance advantage" Note they say "could' not "will".

Most modern ignition coils can provide more than enough voltage to fire the spark plugs; needed for higher compression ratios, various octane fuels, cylinder temps, etc. (This a my personal comment, not that of the NGK article I sourced).  

I found this interesting in regards to heat/operating temperatures..."the addition of the precious metal portion of the center electrode contributes only a small amount of heat and is not a source of pre-ignition."  

"Reeves (the Engineer quoted) emphasized that the heat range rating of a copper-core spark plug and an iridium plug will be the same and that it is the tip (overall) length of the center ceramic that determines any plug's actual heat range."

So not to beat a dead horse, I will close out this discussion with no further response. Thank you to those that responded! Good input!

In summary, my personal reason for considering Iridium plugs was strictly for the possibility of extended plug life and reducing service intervals to checking gap and plug inspection. I am a former auto mechanic so tearing the bike down to perform this function is not an issue. Instead of the Yamaha recommended 4000 miles (plug Inspection), 8000 miles (plug replacement), I would prefer that at the recommended mileage of 26,600 miles to check Valve Clearances at which time to also inspect Spark Plugs, check plug gaps and if needed, replace them.

Safe riding to all! 

 

 

 

[2and3cylinders]

Whereas two plugs can have the same heat range, if their respective reach (center ceramic and metal electrode lengths) into the combustion chamber are too long or short from what the combustion chamber, valve ports, valves, cam timing, ignition timing and intensity, compression ratio, fuel - air mixture, etc. were designed around, there could very well be trouble in River City; however imperceptible initially or even over extended time and mileage.  The FJ/Tracer/XSR/FZ do not have a knock sensor system (does the new MT/T9?), so preignition / detonation, the kiss of death to any ICE, could occur undetected long enough to do serious damage beneath the lovely tones the CP3 sings under load.

I tend but not always (ie., chain slack, rear axle nut and sprocket pretension, wind screen structural integrity and adjustment) to trust the engineers who designed and presumably tested the vehicle knew what they were doing...

 

[texscottyd]

@MrClean731- I appreciate the information, and think it's always welcome here.   I love the idea of extended plug life with equivalent/better performance, which is why I am very interested in the topic.  The stats you provided about the electrode length of the various plug options was the first time I've seen that documented; helps to quantify that there are multiple factors in play.  

To the point that @skipperTmakes about anecdotal observations, my experience with a low-revving 5.7 liter V8 doesn't really translate to the CP3.   The odd thing for me was that the same NGK iridium plugs worked flawlessly in my wife's Grand Cherokee, with the supposedly identical engine...  go figure