Pro shops are tools...

[Andrew Shadow]

Somebody he'p the boy. This now has me confused a bit. Can someone please share the CORRECT NGK number for an '07 ST? How about the CORRECT iridium plug for this bike? I've run iridium plugs in my Valkyries off and on, but really don't see, hear, feel, or even notice a difference between the two, except for the price. I live in Texas, but my ST goes all over North America.
Thanks for the clarification.

Simple to figure out- buy the NGK or Denso spark plugs Honda lists in their manual. No muss, no fuss, they work perfectly fine, and they are cheaper.

I never understood the desire for using overpriced iridium plugs in an engine that was not designed for them. Many people claim all kinds of improved performance but I'm skeptical that it isn't placebo. I bet that in a blind butt-dyno test most riders wouldn't have a clue which plug is installed.

 

[Larry Fine]

I'm under the impression that the only real benefit is longevity.

 

[Igofar]

A local Honda dealership was selling NGK iridium plugs at the cash register in a display box.
I pulled up the NGK website on their computer, and pointed out several things that were wrong with the plugs they were selling.
Like the email address, missing markings on the boxes, crush washers that fell off when the plug was raised, the logo was crooked and in the wrong place etc.
Seems the shop found d a "good deal" on amazon, or Rock Auto, and purchased a big box to pass the savings (yeah right) onto the customers.
The whole box were knock off's.
So I would not blindly follow any/all advice from a parts counter person just because he works at a Honda shop.
Question things, and verify, before you hand out your hard earned money, or damage your bike, trying to save a few bucks.
That's just my opinion.

 

[Andrew Shadow]

I'm under the impression that the only real benefit is longevity.

I have seen that written as well, and then the author goes on to state that they change them at 16,000 miles instead of 12,000 for the standard ones or something equally ridiculous. Spark plugs are often changed prematurely for no real benefit in my opinion.

I changed my ST1300 plugs at 60,000 miles and only did so because I had already bought them. If I hadn't, the originals would have gone right back in because they were still in good shape. Changing them offered no drivability improvements and the fuel consumption remained the same.

 

[Chris09]

I have an aversion to those skinny electrodes, I wonder if it's ever happened with an ST but I had [twice] used some brand of iridium plugs [whatever lordco or canadian tire handed me] in a ford 4.6 that after a few thousand k the electrode eroded below the ceramic. I remember they were two different brands so I didn't think I was making the same mistake twice. The first time there was a noticable loss of power at moderate load / rpm. The second time the condition didn't become apparent until the vehicle was being driven on the Coquihala highway [probably under considerable load].

 

[The Dark Shadow]

If you asked the shop to install iridium plugs they installed the proper iridium NGK plug for the ST1300. You might find someone that disagrees with Honda's recommended spark plugs but the shop followed correct protocol in doing what you asked them to do.

According to the attached chart and owner/shop manual the upgraded plug you asked for is the #7385 CR7EIX. This is the standard heat range plug that Honda recommends in the owners and shop manual - upgraded to iridium. According to the attached pictures of Honda manuals the "forum recommended plug" is too cold for normal operation.

Given you live in a cooler climate and probably don't run at high speed for extended periods of time the heat range 7 is likely what most owners would install.

The CR9EHIX9 are a heat range too cold for the ST1300. There is a common misunderstanding here that because the ST1300 throws off so much heat a colder heat range plug reduces heat to the rider. This is simply wrong and could lead to the engine fouling plugs because the tip of the plug runs below the design temperature that creates the self-cleaning effect. The temperature of combustion in the cylinder is what determines how hot exhaust gas is, not the heat range of the plugs installed.

https://www.ngkpartfinder.co.uk/assets/Uploads/NGK_Upgrades.pdf

I won't dispute heat range differences.

But you 100% failed to respond to what I pointed out about collar vs no collar, AND your points confirm what I said about the missing "H" and "9" in the plugs my local "pro" shop installed.

THEY ARE WRONG FITMENT PLUGS!!

Here's an interacting article. The iridium ngk plugs that fit the st13 seem to come only in heat ranges of 8 and 9, based upon my searches.

It seems possible that iridium plugs require a slight shift in heat range... from 7-8 to 8-9.

I'm not a pro on this. For the cost of a tank of gas, now I'm interested in ordering some 8 range iridiums also to compare against performance with the 9's.

I'll repeat once more...

The plugs the "pros"installed are incorrect fitment, as ALSO confirmed by Guru Larry Igofar.

You may find this article interesting.

https://www.enginelabs.com/engine-tech/ignition-electronics-efi/the-great-spark-plug-debate-separating-fact-from-opinion/

 

[dduelin]

Just read the Honda fitment then look on the NGK chart. There’s really no need to look beyond Honda’s and NGK’s information. Counterfeit parts are a red herring and have nothing to do here with choosing the correct plug.

If you choose to run outside of manufacturer’s recommendations that’s your business and that is fine but the narrative that the dealer installed the wrong plugs is wrong.

 

[The Dark Shadow]

Just read the Honda fitment then look on the NGK chart. There’s really no need to look beyond Honda’s and NGK’s information. Counterfeit parts are a red herring and have nothing to do here with choosing the correct plug.

If you choose to run outside of manufacturer’s recommendations that’s your business and that is fine but the narrative that the dealer installed the wrong plugs is wrong.

Again, you ignore what I stated and what Igofar so kindly pointed out to me.

LOOK AT THE PLUG PHOTOS!

THE FITMENT IS DIFFERENT!

I don't know if you are simply an ego-maniac or if you honestly missed my points and photos about the fitment being wrong...

Collar vs no collar...

"H" and "9" either included or omitted in the spark plug number.

Very strange that you persistently avoid even responding to these clearly important points...

Anyhow, you do you...

God bless!

 

[The Dark Shadow]

I'm under the impression that the only real benefit is longevity.

I'm not a pro and always humbly admit to this...

I found this article that I posted in a separate reply, but I thought you might find it interesting. According to this, there may be some other advantages of iridium plugs. High efficiency (electrical usage), lower stress on the ignition coils, lower voltage required...

I'm not a pro...

I'm not a pro...

I'm saying this twice because some other people might jump on me saying, "You're wrong you're wrong!"

I assert nothing about plugs other than the ones installed for me by the "pros" were the wrong fitment.

Cheers mate!

You're one of the good guys. I don't remember you ever asserting ego.

https://www.enginelabs.com/engine-tech/ignition-electronics-efi/the-great-spark-plug-debate-separating-fact-from-opinion/

 

[The Dark Shadow]

Thanks as always!

Seems according to your diagram that along with wrong fitment, the plugs they installed could be counterfeit. (Gaskets...??)

You know I'm not an expert, but I don't think plugs should have so much wet buildup as these...

 

[dduelin]

Again, you ignore what I stated and what Igofar so kindly pointed out to me.

LOOK AT THE PLUG PHOTOS!

THE FITMENT IS DIFFERENT!

I don't know if you are simply an ego-maniac or if you honestly missed my points and photos about the fitment being wrong...

Collar vs no collar...

"H" and "9" either included or omitted in the spark plug number.

Very strange that you persistently avoid even responding to these clearly important points...

Anyhow, you do you...

God bless!

Thank you and God bless you as well!

I'm simply trying to help you get the plugs you want in your bike. If I'm wrong I'll say so but I'm still trying to see why you think your pictures are relevant. Yes I looked at them in the first read and several times since.

Look at the plugs the dealer installed. That will tell the tale.

NGK doesn't print a separate box for each of the hundreds of plugs they retail with a photo of the exact plug inside - in NGK product advertisement pictures they use generic boxes with a blank spot where the stock number is. The real box will have a 4 digit stock number in big bold black numbers in the white rectangle that is empty in your pictures. Your pictures don't show the product code on the box or on the plug they installed. Take a clear picture of the plug showing the alpha numeric code stamped on the metal body and printed on the insulator. Maybe it's CR7EIX which matches 7385 you referred to earlier.

Here is a picture of a NGK CR8EH-9 showing the code locations. Note the metal stamping omits "9" but it is a CR8EH-9.





Then look at this series of pictures from NGK's part finder:





The two Honda recommended plugs upgraded to iridium are #7385 and #3797, at least according to Honda and NGK. You may choose to go outside these recommendations of course but if you asked the dealer to "install iridiums" without specifying the plug it's likely they followed Honda's recommendation of 7385.

What is the code on the plugs they installed in your bike?

 

[St-Gerard]

High speed, heavy load ,longer rides you may want a cooler plug . Short rides in town most of the time run a hotter plug to burn off carbon deposits, cheers

 

[Larry Fine]

 

[Igofar]

Just read the Honda fitment then look on the NGK chart. There’s really no need to look beyond Honda’s and NGK’s information. Counterfeit parts are a red herring and have nothing to do here with choosing the correct plug.

If you choose to run outside of manufacturer’s recommendations that’s your business and that is fine but the narrative that the dealer installed the wrong plugs is wrong.

What part did you miss about the dealer installing a knock off plug?
It seems everyone is trying to use different wording to support their opinion.
I don’t care what the letters, or range is shown on THOSE plugs that were installed by a shop.
The point y’all should be arguing about is whether they were real, or knock off plugs.
Knock off plugs can list any number or range, this is what they do to sell stuff and rip folks off.
As pointed out, there is nothing wrong with the OEM recommendations provided they are real plugs.

 

[dduelin]

What part did you miss about the dealer installing a knock off plug?
It seems everyone is trying to use different wording to support their opinion.
I don’t care what the letters, or range is shown on THOSE plugs that were installed by a shop.
The point y’all should be arguing about is whether they were rear or knock off plugs.
Knock off plugs can list any number or range, this is what they do to sell stuff and rip folks off.
As pointed out, there is nothing wrong with the OEM recommendations provided they are real plugs.

That's why we need good pictures to see if the plugs look legitimate and are the correct ones. One can't tell anything pointing to counterfeits from the pics posted so far - or I can't anyway. What do you see in the pictures that indicate the shop installed counterfeits?

The narrative delivered is the shop is incompetent but so far we haven't seen any objective evidence of that only a statement that 7385s were installed which according to Honda & NGK are the correct ones for a ST1300 in normal operating conditions. If you see counterfeit, please elaborate how you come to that conclusion and we will all learn something.

Perhaps this is the underlying problem: "According to this forum, the iridium recommended plugs are cr9ehix9 (#6216)."

 

[ToddC]

 

[The Dark Shadow]

Thank you and God bless you as well!

I'm simply trying to help you get the plugs you want in your bike. If I'm wrong I'll say so but I'm still trying to see why you think your pictures are relevant. Yes I looked at them in the first read and several times since.

Look at the plugs the dealer installed. That will tell the tale.

NGK doesn't print a separate box for each of the hundreds of plugs they retail with a photo of the exact plug inside - in NGK product advertisement pictures they use generic boxes with a blank spot where the stock number is. The real box will have a 4 digit stock number in big bold black numbers in the white rectangle that is empty in your pictures. Your pictures don't show the product code on the box or on the plug they installed. Take a clear picture of the plug showing the alpha numeric code stamped on the metal body and printed on the insulator. Maybe it's CR7EIX which matches 7385 you referred to earlier.

Here is a picture of a NGK CR8EH-9 showing the code locations. Note the metal stamping omits "9" but it is a CR8EH-9.





Then look at this series of pictures from NGK's part finder:





The two Honda recommended plugs upgraded to iridium are #7385 and #3797, at least according to Honda and NGK. You may choose to go outside these recommendations of course but if you asked the dealer to "install iridiums" without specifying the plug it's likely they followed Honda's recommendation of 7385.

What is the code on the plugs they installed in your bike?

The photo of the plug you shared shows the "collar" that isn't present on my plugs. It is precisely those missing collar that tipped off Igofar as to the issue. And look at the wet goop buildup on my plug photos. Again, I'm no pro, but from what I've been learning, this means the cylinders are running really rich or are having incomplete combustion.

 

[dduelin]

The photo of the plug you shared shows the "collar" that isn't present on my plugs. It is precisely those missing collar that tipped off Igofar as to the issue. And look at the wet goop buildup on my plug photos. Again, I'm no pro, but from what I've been learning, this means the cylinders are running really rich or are having incomplete combustion.

I took the reference photo of a standard CR8EH-9, not an iridium electrode CR7EIX 7385 plus these are two heat ranges apart so the depth of the nose or insulator will not be the same. Standard plugs vs iridiums will not look the same at the tip much less different heat ranges. It's pretty simple to take good photos to prove your plugs are legitimate NGKs, incorrect spec for the bike, and prove your point (and me wrong) unless you are under pressure not to provide pictures.

It's not easy to read an engine's condition from a random look at the plugs. A plug needs to reach design operating temperature and be moved immediately for examination. The plugs in an engine that was idled or run under light load for 15 minutes vs plugs removed immediately from an engine run for 2 hours at 60 mph will read differently. To your suggestion however, a wet dark look could indicate a plug with too cold heat range.

Do your 7385s look like these in tip construction?

 

[The Dark Shadow]

Since you're enjoying this one with your popcorn, Todd, I figured I'd reply to you... For no other reason than for your enjoyment. What I'll post below isn't a response to you... It's a general response to several other people who have been "piling on".

1) Okay, so I found the cr9EHIX-9 "recommendation" in two other older threads on this forum. The riders using these plugs report the plugs look fine after many miles of riding. So, if that is the case, it SUGGESTS (doesn't prove) that these plugs will be fine and not lead to extra carbon buildup.

2) I am NOT an engine engineer, nor do I have any capability of running several different motors to run tests comparing spark plugs with one another, but from what I have been reading and from speaking with auto mechanics, it seems the case that spark plug inspection is a simple and fairly effective way to determine if one's engine is running lean, rich, or within the sweet spot range.

3) Whether my "pro" installed iridium plugs are counterfeit or not, they are the wrong fitment. I looked on NGK's site for codes, and the "H" (which I thought meant "Honda"), actually means "half thread". Hence, the extra "collar" in lieu of the full 19mm thread length. The member(s) who insist that the "pros" put in the right plug seem to continually avoid this point, and the fact that the plugs the "pros" installed are NOT even the correct code plugs. As DDuelin posted in a photo of the manual, the Honda specified plugs are clearly CR7EH-9 or CR8EH-9. The plugs the "pros" installed are CR7EIX. "IX" is the NGK code for iridium. There is no "H" present in the plugs the "pros" installed, which is clearly specified by Honda. The plugs, while having an acceptable heat value, have a different shape and fitment. Logically, this will have some effect on the performance of the plugs.

NGK Automotive Spark Plug Catalog v1.0

This interactive flipbook is created with FlippingBook, a service for streaming PDFs online. No download, no waiting. Open and start reading right away!

online.flippingbook.com

4) Continuing from #3, both the specified NGK and Denso plugs do not have full 19mm length threads. They both have a "collar" - a thicker non-threaded portion of the "barrel" of the spark plug that protrudes below the sealing gasket. Logically, there is a damn good reason that Honda specifies these shaped plugs. Why...? I dunno... Perhaps the "collar" adds more contact with the engine casing, keeping the plug body warmer so that it can reach the proper minimum 500 degree Celcius carbon burning temperature.

5) Continuing from numbers 1 and 2 above, it is consistently reported that the smaller iridium tip produces a "more powerful" spark (for lack of better description). A more powerful spark will help with complete combustion. And this could logically follow then that even a slightly lower heat range iridium plug could still produce a very satisfactory ignition leading to complete combustion. Again, I am no engine engineer, and I cannot confirm or deny the "quality" of iridium sparks versus copper sparks.

6) At any rate, life is an exploration... Spark plugs, even iridium plugs, can be purchased for about the price of a tank of gas. And I can change them myself. I've ordered some Denso iridium plugs (heat value of 8) and am going to order another set of NGK's (heat value 8) that have the CRITICALLY important shortened threads and included "collar". My bike didn't blow up with the wrong-fitment cr7eix NGK's, although the plugs show definite signs of wet "tar" build-up. I will NOT use these plugs again, as per Larry's advice. (Actually, it was more like a directive, or an order, rather than advice... lol) I appreciate his kind help and his knowledge. I truly never intended to learn even half as much about ICE engines (I know, redundant redundancy - Internal Combustion Engine Engine - that's like Japanese place names translated to English - "Mount Fuji-san" = Mount Fuji Mountain, or Lake Hamanako = Lake Hamano Lake... rotfl), but as I'm learning more, I am becoming more competent with maintaining my wife's car, and my new-to-me 13 year old Toyota BB (Scion xB in North America).

Summary:

The "collar" is critical! Likely it allows more engine casing heat to permeate the body of the spark plug, keeping it at a high enough temperature to burn off the carbon (above 500C). (Refer to the 3 photos attached - 2x specified plugs, Denso and NGK, and 1x alternate iridium version of the NGK, and note they all have collars. While the Denso is slightly different shape than the NGK, it is clearly present. I'll measure the diameters and heights of the NGK vs Denso collars once they arrive and post for everyone's interest and popcorn eating fodder for thought...)

The "pros" installed plugs that do NOT have this collar, and hence are WRONG WRONG WRONG!!! And the proof is the wet black tar buildup. (Look at my photo in an early post in this thread.)

I think I'm done for now... The floor is open for piling on... But there's no need to repeat that the "pros" did not install wrong plugs. They DID install wrong plugs, and we're well past that point already...

Cheers mates!

 

[The Dark Shadow]

Look at my new post above...

You, again, are missing the "H", lad... You're missing the H...! The critical "collar" that is clearly called for by Honda, and that you have shown me earlier a photo of the manual clearly requiring plugs with a "collar" in lieu of complete 19mm threads...

Happy Sunday!!