Pro shops are tools...

[dduelin]

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!!

And you are missing the NGK cross reference chart for upgrading to iridiums from the Honda recommended plugs. It's so simple.......

I think we are done here. Enjoy the upcoming riding season on your motorcycle!

 

[The Dark Shadow]

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?

Apologies... Maybe I have an ego and obstinance problem as well...

You have posted misnomers and you STILL have not addressed the "missing H" (collar)...

The photos above in your reply are CR7EIX, NOT the CR7EHIX-9, and are MISSING the "collar" that is CLEARLY existing in the recommended plugs as per the Honda service manual.

You can search YouTube, this forum, and talk to auto mechanics who will pretty much unanimously state than an easy way to assess your engine burn is by looking a the spark plugs. Too rich will show, too lean will show. The sweet spot will show.

You stated: "It's not easy to read an engine's condition from a random look at the plugs." I am bold enough to say that I expect 99% of auto-mechanics will disagree with this and state that examining spark plugs will give a very good indication of the combustion quality - lean, rich, or in the sweet spot.

Here's just 2 of these 99% of auto mechanics... The first guy even diagnoses much more than lean, rich, or sweet spot.

Near 5:30 in the above video is similar, but more extreme, to what is happening with the CR7EIX plugs in my bike. My suspicion is that because of the lack of collar on the CR7EIX (missing "H") there is less heat being transferred to the body/barrel of the plug, and it is not staying hot enough (500C) to burn off the excess.

Anyway, whatever... Feel free to install plugs without the collar, and see what happens to them in your bike.

 

[Andrew Shadow]

Reading this forum there are quite a few posts by people who have switched to iridium spark plugs and who have gone through the very same fitment problems and confusion as you are having. As I have yet to see a tangible benefit I just use one of the spark plugs listed by Honda and forget about the whole cross-reference saga.

Not directed to you specifically Mr. Shadow, but to anyone in general who can explain it to me, and regardless of all of the above, I am curious to know what problem will be resolved or what benefit will be derived by switching to iridium spark plugs. I ask because I have read many posts on this forum about them but have yet to see any real concrete benefit quantified in a meaningful way. As such, I still do not understand the reason for the switch. Better tires yield better performance, better shocks yield better performance, better light bulbs yield better performance, etc.. Is this a case of better spark plugs yield better performance, or some other benefit? If so, what is that real-world tangible benefit that they provide over the spark plugs specified by Honda?

I should state in advance that the argument for longer replacement intervals is a non-starter with me.

 

[bdalameda]

Every few years the dreaded conversation pops up about the Honda "H" vs non-H spark plugs. Yes Honda's spark plugs produced by Denso or NGK have an unthreaded portion on them. There is much speculation of why Honda did this that range from heat transfer to having to buy plugs only at Honda dealers to find the H version plugs as well as giving an indentation as a guide to start the plug threading into the head to prevent cross-threading during installation. The critical part is the dimension is the distance from the gasket surface to the plug tip. This distance is the same on both the H plug and the non-H plug. The fit of the unthreaded portion of the plug is not tight enough in the head to increase heat transfer so I don't think that is why Honda specified this. Almost all heat transfer is from the center insulator through the plug body into the gasket mating surface. The length of the center insulator dictates the heat range of the plug. You can run a non-H plug without causing any harm to anything. Dimensionally the plugs are the same. The #7 is the heat range of the plug, the letter C is the thread size and the R is for a resistor plug. I have run non-H plugs for years without any problems as well as many others. Honda designates the H type plugs in the CBR600-1000's years back and I know of a lot of road racers that did not use them as their preferred plugs are not available in the H series. There were no problems using a non-H plug.

Now a couple other tidbits - Igofar makes a very good point about counterfeit plugs. There are a lot of counterfeit NGK plugs around. Buying spark plugs from Amazon is a real cr@pshoot about what you may get. Many dealers are also buying discount plugs and don't know they are counterfeit. These counterfeit plugs have caused some people a lot of grief.

Now Iridium vs standard plugs - Iridium plugs increase service life over standard plugs - the Iridium erodes far less than the standard electrodes. The reason that the iridium plug tips are smaller and thinner is mainly due to the fact that the iridium material does not conduct electricity as well as the steel/copper electrode. The smaller thinner electrode is necessary to reduce the energy requirement to make a spark. One advantage to a smaller/ thinner iridium tip is that it allows better exposure to the combustion chamber and less shadowing of the plug tip. This can make a larger faster flame kernel form when combustion occurs and improve combustion slightly. Not by any huge or measurable amount. I have noticed that running Iridium plugs in large cylinder bikes like a KLR650 or Airhead BMW's can produce a smoother idle. I can't say that an iridium plug makes any noticeable different in a ST1100 or 1300.

 

[motornut]

I hope that this will make a very small ripple in the discussion about plugs and in no way denigrates updating your plugs to a higher plug style, but I have run stock OEM plugs in my truck, expedition, all four of my motorcycles.
In my ST I have changed plugs once in 122000 miles and it ran fine before and after, once in my pickup in 184000 miles, never in the Concours in 37000 miles and never in the ZRX in almost 40000 miles.
With the fuel injection I have seen plugs go a really, really long time unless something is wrong inside, fouled plugs are very unusual and mostly from injector failure. This is the benefit of mixture control. Although the ZRX is carbed it was tuned on a dyno and the guy who ran it on a dyno told me not to touch anything, the power band was perfect, and the mixture was perfect also.
The main reason for me to pull plugs on them early is to put a bit of anti seize on them.
My Expedition has the fabled plugs that break on removal and I changed them because of a injector failure. And of course like a idiot I changed the coils first because they commonly fail when I should have followed my own advice and looked at the plugs. Too lazy I guess, well not a guess it was because I was lazy.
It always been my first step in troubleshooting short of scanning for codes. Reading the plugs tells you what is going on inside.

In a side note I will not buy a vehicle from most mechanics ( including myself ) because I can booger things up to the end of its life span. The only reason for it being on the market is because I am tired of fixing it and its used up.

 

[The Dark Shadow]

Response to the last 3 posts...

Thanks.

Long and short... I don't know but I like to learn.

Igofar identified that my plugs were wrong, I believe because of the lack of collar.

Perhaps they are genuine NGK, perhaps they are knock offs. According to the chart Igofar posted, they don't seem like knock offs. I don't know and likely never will.

Iridium versus standard... In the multitudes of readings I've done on the subject, there is a consistent description of a "more powerful spark" leading to "greater explosion propagation" (or descriptions similar to this). Since I am not a hydrocarbon or air atom inside the combustion chamber, I cannot confirm or deny any of this, but have to gather information from people more knowledgeable and experienced than I on the matter.

Continuing, it seems consistently stated that iridium plugs can give an easier start up, smoother idle, and quicker power transition when throttling up. Some claim (but I have not seen any comparisons) that fuel economy can improve. If indeed the spark is better quality which leads to more powerful explosion and more complete combustion, then it logically follows that fuel economy will be improved.

When we replaced the spark plugs in my Toyota Venza, I got an immediate MEASUREABLE (not psychological) improvement in fuel economy compared to the previous standard plugs. From 15.9 l/100km to 14.7 l/100km. The gas savings paid for the plugs and cost of installation in a year. Was this because the old plugs were on their last legs, or because the iridium truly are better, or a bit of both...?? None of you, nor I, will be able to truly compare.

But, what I can do pretty easily, is run my motorbike with different plugs - same route same speed - and measure my fuel economy. I am also a lad gifted (and cursed) with extremely acute senses. So while I'm aware that one needs to be careful for psychological expectations leading to noticing "performance improvements" which aren't truly there, I should be able to notice differences in idle and throttle-on response if there are any to be noticed.

I'm actually pretty excited to try the bike with different sets of plugs (hopefully no counterfeit plugs) to measure and "listen" with my acute senses to see if indeed there are any differences, or no differences. Of course, I will be glad to share my results with all of my st1300 riding brethren on this forum.

And for my Shadow brother, Andrew, here's a repost of an interesting link about spark plugs that I posted earlier in this thread.

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

And here's another interesting and informative article I read today.

https://www.motortrend.com/how-to/10-factors-that-affect-spark-plug-heat-range/

God bless you all!! No matter whether you ride with a collar, or not, rubber side down!!

Cheers!

 

[Al st1100]

If so, what is that real-world tangible benefit that they provide over the spark plugs specified by Honda?

I should state in advance that the argument for longer replacement intervals is a non-starter with me.

Platinum and budget iridium plugs last around 60,000 miles. Double platinum and premium iridium plugs can last 100,000 miles or more.

 

[Sadlsor]

I never understood the desire for using overpriced iridium plugs in an engine that was not designed for them.

As this thread has already run off the rails a couple of times, I don't mind so much addressing this specific concern, so...

I'd imagine it's for much the same reason some people will swear by synthetic oils, or adding velocity stacks, or headers and slip-ons or trying to find other ways to get more power out of the engine, regardless of design intent. Honda recommends certain products and certain specifications for bikes designed a certain way, for a certain performance level.

It's in the nature of some riders (and some drivers) to tweak, adjust and experiment with their machines. I'm not one of those, and I'm certainly no Soichiro Honda, nor Kevin Cameron, so mostly I'll just leave stuff alone except for some creature comforts.

But in the end, I don't judge those who may be more skilled, or more curious, than I am. When it comes to motors, I want them to be predictable and reliable more than anything.

So remind me again -- what's the best oil to use in our ST? KIDDING!!!!

 

[bdalameda]

Guess what - NGK is now making a new type of spark plug called a Ruthenium plug. Supposedly works better in turbo-charged applications. I put a set in my pickup. More to argue about!!!

 

[Larry Fine]

Guess what - NGK is now making a new type of spark plug called a Ruthenium plug. Supposedly works better in turbo-charged applications. I put a set in my pickup. More to argue about!!!

And endorsed by Dr. Ruth herself!

 

[Obo]

And endorsed by Dr. Ruth herself!

So they work like normal plugs but are sexier?

 

[Al st1100]

As this thread has already run off the rails a couple of times, I don't mind so much addressing this specific concern, so...

I'd imagine it's for much the same reason some people will swear by synthetic oils, or adding velocity stacks, or headers and slip-ons or trying to find other ways to get more power out of the engine, regardless of design intent. Honda recommends certain products and certain specifications for bikes designed a certain way, for a certain performance level.

It's in the nature of some riders (and some drivers) to tweak, adjust and experiment with their machines. I'm not one of those, and I'm certainly no Soichiro Honda, nor Kevin Cameron, so mostly I'll just leave stuff alone except for some creature comforts.

But in the end, I don't judge those who may be more skilled, or more curious, than I am. When it comes to motors, I want them to be predictable and reliable more than anything.

So remind me again -- what's the best oil to use in our ST? KIDDING!!!!

imo your not getting any more power just a spark plug that will not degrade over time so it's predictably better over time. As far as oil goes I'm willing to try that extra slutty olive oil.

 

[St-Gerard]

I wonder if NGK still makes the V-Grove plugs , had good luck with them , quick starts and never a misfire even above the redline on the Cbx550f , which yes I rode like it was stolen ,because it had been stolen and recovered( and the bike was to small for me). Anyway not available for the ST1100. Spark plug gap has a noticable effect on performance.

 

[Larry Fine]

As far as oil goes I'm willing to try that extra slutty olive oil.

 

[The Dark Shadow]

FWIW... Some may find this interesting...

Look at photos...

If Honda DIDN'T design the engine for spark plugs with the "half threads" or "collar" as per my descriptive term, surely they'd have said use either of the plugs in these pictures...

Note the inclusion and exclusion of "H" which indicates the half-thread or collar.

I just did some sleuthing, and some of you may be interested in this:

The CR7E and CR7EIX are listed on Fortnine showing a gap of 0.8mm.

The "-9" designation, according to NGK's site, indicates a .9mm gap.

So, if this information is accurate, it shows quite clearly that the CR7E vs CR7EH-9, as well as the CR7EIX vs CR7EHIX-9 are different in 2 clear and concrete ways:

One has "half thread" (collar), the other doesn't.

The plugs without the -9 designation have a gap of 0.8 and the -9's have a 0.9mm gap.

Seems to me that the larger gap will produce a longer spark so will give better explosion and combustion.

Until a couple days ago, I never knew ANYTHING about spark plug heat values, and now I do.

Until today, I didn't know the 2 major differences between the CR7E vs CR7EH-9, and CR7EIX and CR7EHIX-9.

Now I do... And perhaps some of you now know more than you did before reading this popcorn munching thread... LoL

Have a great night, and great week ahead Everyone!! I feel I've succeeded in extending my knowledge!

 

[Larry Fine]

I thought you were never supposed to trust plugs as being pre-gapped correctly.

Question: Is the unthreaded portion in contact with the head or floating in space when installed?

 

[Andrew Shadow]

Platinum and budget iridium plugs last around 60,000 miles.

As will any standard plug in a properly running engine.

 

[The Dark Shadow]

Question: Is the unthreaded portion in contact with the head or floating in space when installed?

That's what I don't know, since I'm not a tardigrade and have never been inside there... As I mentioned in an earlier comment, my logic/intuition (with no proof at all) is that the collar of the plugs clearly required by Honda could help keep the body of the plug warm from the engine casing heat... Your guess is likely as good as, or better than, mine...

I thought you were never supposed to trust plugs as being pre-gapped correctly.

I'm not an expert but based on my readings it seems like older standard plugs has more manufacturing variation, but modern manufacturing standards made them quite accurate.

 

[DannoXYZ]

As I mentioned in an earlier comment, my logic/intuition (with no proof at all) is that the collar of the plugs clearly required by Honda could help keep the body of the plug warm from the engine casing heat...

Logic given proper data & variables:

- combustion temp at spark-plug tip = 500-850C
- head temperature around spark-plug hole = 120-130C

What would you say about this conclusion?

… that the collar of the plugs clearly required by Honda could help keep the body of the plug warm from the engine casing heat...

 

[St-Gerard]

I do check the gap before I install plugs ,NGK's have been dang close to Spec so long as the protective sleeve was on it,and no damage to the box.