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Discussion Starter #1 (Edited)
I did a search, and all the threads seemed to date back to 2010, so I figured there is probably some more recent feedback on the subject. Who has used the NGK CPR7EAIX-9 Iridium IX Spark Plug, and is it worth the extra $6-8 for a pair vs regular plugs? Also, since I have completed the big 3, should that have any affect on the decision?
 

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I did a search, and all the threads seemed to date back to 2010, so I figured there is probably some more recent feedback on the subject. Who has used the NGK CPR7EAIX-9 Iridium IX Spark Plug, and is it worth the extra $6-8 for a pair vs regular plugs? Also, since I have completed the big 3, should that have any affect on the decision?

IMO, it's a matter or personal choice to go iridium or not. I had a 2003 Vulcan 750 that I modified and the forums I was with at the time tried feeding me some stuff about iridium plugs. Supposedly, they have less resistance than standard plugs which gives a better spark. Other than that, I really don't see the need to spend the extra $$$. Maybe in performance applications, the iridiums would be good, but on a cruiser bike like ours, I don't think it's worth it.

Another thing to think about, if your bike ever happens to develop issues that cause the plugs to fowl, you'll be forking over a lot of money to keep replacing those plugs.

Really, the question to use iridium or standard is no different than asking to use synthetic vs. dino oil. It's all a matter of personal preference.
 

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I use the more costly plug. I believe they are better for the bike. For as how often as you don't change plugs, the couple dollars doesn't make a difference to me. I use higher octane fuel instead of reg gas also. Your bike is a high performance machine and will profit from HP parts. That is IMHO
 

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From what I've seen, the main advantage to iridium plugs is that you can run them for 100,000 miles. But if you don't pull the plugs after 20k or 30k miles they'll rust into the head. Once you have the old ones out why not put new ones in? As far as high octane fuel goes, these bikes do not have high enough compression for high octane fuel. These bikes are designed for 87 octane (USA). Using 90 or higher is a waste of $$ and can cause preignition which can damage your engine.
 

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From what I've seen, the main advantage to iridium plugs is that you can run them for 100,000 miles. But if you don't pull the plugs after 20k or 30k miles they'll rust into the head. Once you have the old ones out why not put new ones in? As far as high octane fuel goes, these bikes do not have high enough compression for high octane fuel. These bikes are designed for 87 octane (USA). Using 90 or higher is a waste of $$ and can cause preignition which can damage your engine.
That is wrong! Higher Octane slows the burn and does not cause preignition in any way. That why it used if you get ping (preignition)
 

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I found a definite boost when i changed to iridium @6000mi on my 2012 900classic. My shift points are longer, i can ride 4th right up to 50-55mph before i really need to shift to 5th, it was much earlier before, it also seems peppier in 3rd gear as well, since the manual says to change plugs @7500 mi anyway since the stock ones are standard, i would replace with the iridium anyway, even if you don't believe my claim. They cost me $18. for the pair shipped from spark plugs.com/ the cpr# above is correct, don't get the dpr's...ride on...I always use 89 octane, even in my lawn mower....cheers...
 

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The difference in spark plugs is something I've never really fully understood. If you've got a cheapo plug, wouldn't the comparatively weak spark increase in size and temperature to that of a high-dollar plug in a couple milliseconds anyways?
 

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I've got the iridium plugs and they make no noticeable difference to performance. Only advantage is that they last longer. For the price they are worth it.
 

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Discussion Starter #11
For the whole $16.50, delivered to my door from Amazon, I went with the Iridiums. The plugs were due to be changed, so I can't say if there is any more improvement than what would have been gained with regulars. If the spark stays more consistent, and for more miles, then they are worth the few extra dollars. I'll report after a couple tanks if there are changes in fuel mileage.
 

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The literature from NGK suggests that the plug produces a better burn and thus a slightly better performance. If it's only a few $$ I may look at that next change.
 

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new member here and thought I would add my 2 cents.

I have the big three as well and I added them all about a month a part from each other. I started with the exhaust pipes which really opened up the engine and shift points. I loved the sound as well. The bike was running lean so I added the Cobra CVT tuner next and I felt it more responsive, less popping, and more get up and go from a stand still. The air intake was the third of the big 3 for me and I just really loved the performance of the bike.

I was reading a lot about the iridium spark plugs and decided to pop a set in this past weekend and immediately noticed a difference. The exhaust has a deeper growl to it and when I took the first ride I noticed that the shift points again opened up.

Big three only my shift points were 20mph, 30mph, 45mph and then 55mph. Now these were my max speeds I would get to to shift because the engine just sounded like it needed too.

Now with the iridium plugs I can get up to 25, 35, 45-50, and above 60mph before I need to really kick it into 5th gear.

I only have gone 146.3 miles on them but I filled up today and my avg mpg was 45.25.

hope this helps
 

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Billas, you lost me. If you're getting more power, you can shift earlier. Your top end is determined by valve action (specifically valve float), not power. Though I wouldn't make a habit of it, 4th gear will take you over 80.
 

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Well by that logic i should have left it stock because i had to shift at 12, 20, 26, and 35mph before i made any mods what so ever.

Im basing my shift points on typical riding conditions not gunning it off the line

Im not a mechanic but the butt dyno is happy ��
 

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I use the Iridium too, I would say 12-15k miles ago... there is no difference as far as I can tell.

for starters, one can check the spark plugs for wear and tear... measure the gap, and check the coloration. a simple google will tell you how a spark should look... the coloration also tells you how healthy the motor is running. there are no hidden magic components in a plug: what you see is what you have :}

the Iridium is a stronger material, so it will last you longer. it may also run colder, but I did not have the will to compare the temperature grade of the plugs...

*besides the actual spark, the function of the plug is to transfer heat. there are different temperature grades for spark plugs.
 

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I feel bad, I still have the original set of plugs in mine. 32K I just clean and re-gape every 7-8 K. 87octane w/ethenol,
As far as shift points 2nd)20-25. 3rd)32-35. 4)48-53. 5th) never before 55 most often 60+, the rev limiter dose not kick in tell after 95mph in 4th.
Never owned a Kawi that did not like to rev. 500+ 750 triples/KZ+Z1 900s/ Ninga 650.
 
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