Author Topic: Iridium plugs (Read 5751 times)

bucket · « **on:** December 26, 2023, 05:04:52 PM »

Hi all, the brain is starting to get into gear for an upcoming big trip and my thoughts are turning to servicing. While I'm pretty sure I'm on top of filters and oil, plugs are causing me a bit of a problem. I'm looking at fitting iridium plugs, most likely NGK, but have to decide between cr8ehix-9 or cr9ehix-9. Has anyone had first hand experience with either? i'm leaning towards the 8's for their allrounder ability but am open for change. Thanks.

Update, just found another thread where they recommend cr7ehix-9. the use of my bike indicates to me that the 8's would be a better choice but again, am open to change.

ruSTynutz · « **Reply #1 on:** December 27, 2023, 02:51:21 PM »

Hi Bucket, I'm running NGK CR7EIX Iridium IX Spark Plugs in my ST1300 and have never had an issue with them whatsoever in the 3 1/2 years since I installed them.
From my experience it's cheaper to buy them from the UK (even with shipping costs) than buying them in Oz.

I got mine from here: https://www.driven2automotive.com/shop/ngk-cr7eix-7385-spark-plug/
Cheers

West Aussie Glen · « **Reply #2 on:** December 28, 2023, 08:18:16 AM »

A google search came up with these https://automotivesuperstore.com.au/ngk-cr7eix?utm_term=NGK-CR7EIX&utm_source=bing&utm_medium=cpc&msclkid=8e76b31e834e15ae2492d692223674cc

ruSTynutz · « **Reply #3 on:** December 28, 2023, 09:01:47 AM »

Wherever you end up purchasing them from, just be aware there are a lot of fakes out there...

West Aussie Glen · « **Reply #4 on:** December 28, 2023, 09:52:48 AM »

how do you pick the fakes from genuine?

ruSTynutz · « **Reply #5 on:** December 28, 2023, 10:26:41 PM »

Hi Glen, a quick search on Google will bring up a heap of articles...

Here are a few examples:

https://www.ngkntk.com/newsroom/blog/emea/fake-or-not/

https://www.driven2automotive.com/shop/blog/how-to-spot-fake-ngk-cr9eix-iridium-ix-spark-plugs-2018/

https://thecounterfeitreport.com/product/400/Spark-Plugs.html

bucket · « **Reply #6 on:** December 29, 2023, 03:09:16 PM »

Thanks for the replies, looks like the '7's' might be the go by the sounds of it. I had a set of '8's' lined up through Amazon from the USA at a good price, $65.11 AU delivered. I'll have a hunt around for the others now. Just for reference, I also found these on Amazon. https://www.amazon.com.au/NGK-Iridium-Spark-Plugs-CR7EIX/dp/B0042LRMHW/ref=sr_1_2?crid=1K63EYC9BWNNJ&keywords=NGK+CR7EIX+Spark+Plug&qid=1703826630&sprefix=ngk+cr7eix+spark+plug%2Caps%2C278&sr=8-2

ruSTynutz · « **Reply #7 on:** December 29, 2023, 04:06:09 PM »

Cheers Bucket...

Just be aware that Amazon was one of the companies reportedly selling fakes, as was eBay...

bucket · « **Reply #8 on:** December 31, 2023, 09:08:56 AM »

Thanks for the heads up about Amazon. I was looking closer for some sort of guarantee about being genuine, but couldn't see one. I haven't ordered yet but will make further enquires.

BCinOZ · « **Reply #9 on:** February 27, 2026, 11:23:14 AM »

There’s an in depth analysis of iridium plugs done by a South African bloke.
Why an iridium with an H in the suffix needs to be there.
Type in : Spark plug installation mistakes on Honda st1300
It’s very enlightening.
(I know this is an old thread, but no real need to start a new one I think?)

ruSTynutz · « **Reply #10 on:** February 27, 2026, 03:16:49 PM »

Here's a direct link: https://www.facebook.com/groups/417025506063126/posts/1033355607763443/

Williamson · « **Reply #11 on:** February 27, 2026, 06:05:52 PM »

These days, with electronic fuel injection (delivering an exact measure of fuel) and electronic ingnition (delivering a constant and exact measure of electricity), spark plugs do not foul or wear out as frequently as in the old days.

Our old Mazda6 (180,000km in 15 years) only had one change, my original ST1300 (80,000km in 12 years) also only had one change (at 70,000km).

Ray (the mobile mechanic who lived at the bottom of our street) serviced the Mazda, changed the plugs prior to a trip to QLD. Dave (who serviced the ST1300 since 2016), changed the plugs at 70,000km. Both old sets were clean with no sign of any fouling, they were tested and gave a strong, bright, bluish spark. We concluded that they didn't need to be replaced, but what the heck, leave the new ones in anyway.

My view, save your $$, don't bother with new plugs (unless they're needed), if needed go standard.

BCinOZ · « **Reply #12 on:** February 27, 2026, 07:30:16 PM »

It was more about the type of plug, and its position in the combustion chamber. It’s a very detailed analysis. Bloke had lots of problems because of it.
I only posted because I noticed above people using an iridium without the H in the suffix.
This caused a lot of problems.
I don’t know the history of my bike, and it will be getting stock plugs this weekend.

Williamson · « **Reply #13 on:** February 27, 2026, 07:32:31 PM »

Quote from: BCinOZ on February 27, 2026, 07:30:16 PM

It was more about the type of plug, and its position in the combustion chamber. It’s a very detailed analysis. Bloke had lots of problems because of it.
I only posted because I noticed above people using an iridium without the H in the suffix.
This caused a lot of problems.
I don’t know the history of my bike, and it will be getting stock plugs this weekend.

Jdbiker · « **Reply #14 on:** February 27, 2026, 08:15:01 PM »

Only use NGK CR7EH-9 on mine and change them every 20,000 kms, cost around $7each. Not a great deal of benefit using iridium plugs for the average rider apart from the fact they last a lot longer. I like to pull out the plugs between 10 and 15K to check the engine health👍

West Aussie Glen · « **Reply #15 on:** March 01, 2026, 10:21:35 PM »

Quote from: Jdbiker on February 27, 2026, 08:15:01 PM

Only use NGK CR7EH-9 on mine and change them every 20,000 kms, cost around $7each. Not a great deal of benefit using iridium plugs for the average rider apart from the fact they last a lot longer. I like to pull out the plugs between 10 and 15K to check the engine health👍

When you pull the plugs what are you looking at to check the engine health?

ruSTynutz · « **Reply #16 on:** March 04, 2026, 05:42:07 PM »

After BCinOZ shared the in-depth analysis of iridium plugs by that South African bloke (thanks BCinOZ!) I decided to chuck in some standard NGK CR7EH-9 plugs,
replacing the NGK iridium plugs that I'd had in the bike for approximately 30,000ks.

It will be interesting to see if I notice any difference when it comes to fuel economy and operating temperature......

Here are the old plugs...

Jdbiker · « **Reply #17 on:** March 04, 2026, 08:25:33 PM »

When you pull the plugs what are you looking at to check the engine health?
Report

Colour of the plugs give a very good indication of engine health 👍

Brock · « **Reply #18 on:** March 04, 2026, 09:31:38 PM »

Modern fuels it seems have little effect on the plugs,unlike the old leaded fuels. The colour and heaviness of the deposits used to be a good indication of the performance.

I replaced the plugs in my 1100 at about 150K kilometres. the plugs still looked good and worked well.

Dragonstaff · « **Reply #19 on:** March 12, 2026, 07:40:05 PM »

Quote from: Brock on March 04, 2026, 09:31:38 PM

Modern fuels it seems have little effect on the plugs,unlike the old leaded fuels. The colour and heaviness of the deposits used to be a good indication of the performance.

I replaced the plugs in my 1100 at about 150K kilometres. the plugs still looked good and worked well.

Same here Brock. I changed mine last year, but I probably didn't need to. They looked as good as new after many kilometres.

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Author Topic: Iridium plugs (Read 5751 times)