To go iridium or not?

Dave.David

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Dec 9, 2016
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716
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SB California USA
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05,ST1300-04VTX1800R
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8938
Hi there....lots of great info from this site but I need more :)

I'm going to replace my spark plugs. Since I have a 2008 ST1300 and NGK recommends the standard plug only, ( i have standard Denso in it now) is there anyone on here with the same vintage bike that are using iridiums with no issues? Since the standard plugs are CR7EH-9 , would the iridium be CR7EHIX-9 ? Some sites call for the CR9EH-9 and CR9EHIX-9 for my bike? I have the Denso U22FER-9 which is the same as the NGK CR7EH-9

What's the purpose of the inner black cowls? Are they to direct air to cool the engine? I'd like to drill a few holes in them to help with the heat dissipation in the summer time. (i haven't experienced a summer with the bike yet either, just trying to get prepared) Some have made large holes in them and some have removed them. What's the feeling on that?

thanks
So do we agree. CR8EHIX-9 is the way to go?
 
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Kevcules

Kevcules

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Started my steed today after some winter maintenance including the iridium plugs. Started fine , ran smooth, I don't anticipate any issues. I'll know for sure once I get a few runs in, not for a while yet though.
 
Joined
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Alief, TX, USA
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ST1300
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7461
The original iridium plugs in my sons 2002 Honda Civic Si were changed at 187k miles and they looked just fine. Also, I use iridium plugs in everything I possibly can, and have for years. As long as you do not have oil or fuel/air mixture issues, they will last way over 100k miles.

I cannot attest to the holes in the inner fairing thing only that I am always reluctant to drill holes in anything on my bikes. I figure the engineers that designed the things know more than me.
+1 on both points. Iridium plugs for sure. I wouldn't recommend any drilled holes or other mods until at least yo have ridden it a few hundred miles and decide that it needs something done to correct a problem. I've never had a real heat issue with my 03.
 
Joined
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Kenly NC
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07 ST1300A(P)
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7649
The aging mechanic in me always uses the factory plugs, figure if it's good enough for the manufacturer, it's good enough for me. Champions in most chryslers, NGK in the hondas, bosch in the germans, motorcraft in the fords, and so on and so forth. I tend to pull the plugs in vehicles that advetise 100,000 mile plugs, and lube the threads. Fords triton motors taught me that.
 
Joined
May 6, 2011
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Vancouver, WA
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2007 GL1800
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8714
I'm going to replace my spark plugs. Since I have a 2008 ST1300 and NGK recommends the standard plug only, ( i have standard Denso in it now) is there anyone on here with the same vintage bike that are using iridiums with no issues? Since the standard plugs are CR7EH-9 , would the iridium be CR7EHIX-9 ? Some sites call for the CR9EH-9 and CR9EHIX-9 for my bike? I have the Denso U22FER-9 which is the same as the NGK CR7EH-9
When I did my 16,000 mile service, I replaced my spark plugs. But, for the life of me, I could not find the correct standard plug anywhere. So, I was forced to use the iridium plugs. After much research and agony I found and installed NGK CR9EHIX-9 Iridium Plugs. (The standard was: NGK CR9EH-9 Standard Plug). I've been using them for the last 16,000 miles. They still look very good, and have performed without issues.

The difference between a CR9EHIX-9 and a CR7EHIX-9 is the heat rating. The FIRST "9" in the plug number represents the heat rating of the plug. For NGK, the higher the number, the cooler the plug. NGK heat ratings range from 2 - 11; Two being the hottest, eleven being the coldest.

As for the inner cowling, check out this thread: https://www.st-owners.com/forums/showthread.php?27114-Question-for-ST1300-owners-that-have-removed-the-inner-cowling&highlight=inner+cowling
 
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Kevcules

Kevcules

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When I did my 16,000 mile service, I replaced my spark plugs. But, for the life of me, I could not find the correct standard plug anywhere. So, I was forced to use the iridium plugs. After much research and agony I found and installed NGK CR9EHIX-9 Iridium Plugs. (The standard was: NGK CR9EH-9 Standard Plug). I've been using them for the last 16,000 miles. They still look very good, and have performed without issues.

The difference between a CR9EHIX-9 and a CR7EHIX-9 is the heat rating. The FIRST "9" in the plug number represents the heat rating of the plug. For NGK, the higher the number, the cooler the plug. NGK heat ratings range from 2 - 11; Two being the hottest, eleven being the coldest.

As for the inner cowling, check out this thread: https://www.st-owners.com/forums/showthread.php?27114-Question-for-ST1300-owners-that-have-removed-the-inner-cowling&highlight=inner+cowling
"

thanks for the info...

I also went through a bit of pain trying to find the iridium equivalent to the standard denso plug that my bike had in it. Since my manual says my bike could take either a NGK 7 or 8 plug, I found some CR8EHIX-9 for my bike. So I'm within the temp rating. I didn't want to try the "9" in case it was too cold of a plug. Good to hear it's working ok.

I was going to drill a few holes in my inner cowling today, but couldn't find my hole saw bits so I installed all the tupperware without issue. I was surprised that it wasn't too bad, even after being off for the last few months. I'll wait to see if I have any heat issues this summer.
Thanks for the link. I already read that thread and that's what gave me the idea to try the holes.
 
Joined
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Vancouver, WA
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2007 GL1800
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I didn't want to try the "9" in case it was too cold of a plug.
I know what you mean. I had tried to get a -7 or -8 temperature plug, but couldn't find any in my area. With trepidation, I went with the -9 plugs. So far I haven't had any issues. Also, I mostly do long rides
 

MajorTom

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Apr 1, 2010
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Devon, Alberta
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I just checked my iridium plugs today (NGK CR9EHIX-9) while performing a valve check. Just over 77k km on the plugs and they look like all they need is a brush and a gap adjustment. The ceramic around the electrode is a light tan.
 
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Kevcules

Kevcules

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Good to hear the -9 plugs are ok. That means our bikes aren't too picky with what plug they have. :) I remember a few sites that I visited gave me that -9 plug as what my bike needed. I used partzilla and I was able to search the -8 iridium plugs and order them even though they too recommended the -9 ? What gap did you guys use anyways? The manual gives a broad range.... .031" to .035" I used .034" , maybe I should have gapped them smaller?
 
Joined
Nov 23, 2005
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147
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Central South Carolina
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03 ST1300A
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6000
After reading the thread, I'm taking it that the CR8EHIX-9 are the correct iridium plugs? I'm thinking to change mine out soon, and deciding whether to go stock or not. The bike seems a little slow to start, and by that I mean the starter has to turn over more than it should to get the bike started. Since I've no idea when the last real maintenance was done, I'll do it myself. Since I know my limitations, I'm trying to find somewhere to get the valves checked/adjusted. My local Honda shop is fairly useless, and I only go to them for accessories and parts I'm in a hurry for.

Interestingly enough, seems the heat issue with the 13s is like the "Connie vibe" issue with the Concours 10s. Some people seems to feel it more than others, or some bikes don't have it as bad. Seems to depend on your POV. I have a 2003, and so far, I'm not noticing a heat issue. Don't recall much of one on my '04. It hasn't been terribly hot here since I got the bike in Feb, maybe mid 80's, and I haven't looked up under the plastic much yet, so no telling if the PO has done any heat control mods.
 
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Kevcules

Kevcules

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Does anyone have advice on what gap to use with the iridium plugs?
Check my post #30 Manual says .031" to .035" I checked the plugs I bought and they were about .034" so I left them there.
 
Joined
Jul 20, 2006
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44
Location
Milwaukee, WI
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ST1300
Thanks for the info. I put my first set of Autolite iridiums in this week, and I gapped them to .033 I will plan to pull two of them after 10,000 miles to see how they look.
In pulling the old NGK plugs I noticed that the two back cylinders came out a bit blacker than the two front cylinders.
The two forward looked a very nice, slightly tan/ash gray color, but the two back plugs looked noticeably darker. I would not go so far as to say that they were "oil fouled" but they definitely showed more black than the front two.
Is this normal for the 1300?
 
Joined
Jan 7, 2014
Messages
4
Location
Columbus, Ohio
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2009 ST 1300
Hey all. A little help, hopefully. I bought an ST1300 tune up kit from Amazon that included air filter, oil, oil filter and 4 spark plugs. The plugs are Honda-labeled NGK DPR7EA-9. That doesn't match either option in the book for my 2009 ST 1300. Are these a good replacement? I cant seem to find any comparison data. Thanks!
 
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