I owe someone here on the Clinic a huge apology!

I was of an erroneous opinion that the NGK Iridium plugs many of us have put in our bikes would last... forever. I now believe I was TOTALLY mistaken, but argued for my point with someone here just a couple of months back.

Here's the story, and the facts as I now understand them. A friend with an '03 4-cyl Camry needed a sticker, but his check engine light was on. So, we went to Autozone and the OBD diagnostic handheld said he need the O2 sensor before the cat. No problem. We buy one and put it in easily.

I had also disconnected the battery in order to reset the car's OBD computer. Upon restart, it stumbled badly and would stall, and the light came back on. My friend then went to another friend who runs a garage and does state inspections. He puts his handheld on and the codes come back about cylinders 1, 2 and 3 misfiring! He tells him that when you replace a sensor, you usually have to do a tune-up by replacing the plugs... so, my friend buys a set of NGK BKR6EIX-11 Iridiums for his car, and comes back to me.

Now, I'm thinking... this sounds like a buncha BS... but, because the guy said, replace the plugs and come back, and he'd reset the computer and give him a sticker, I put his new Iridiums in.

WELL, guess what I'm unscrewing from his plug holes, but NGK Iridiums, and they were SHOT!!! That's right, the center electrode is Iridium, which is hardened platinum, and will last probably forever. BUT, the outer, 90 degree bent electrode is definitely not iridium, and whatever it is... probably the same as with most any other plug... that stuff burns and wears away and the gap just keeps getting wider!

Here's the end of the story. My friend is quite certain the iridiums I removed had only been put in 70,000 miles before.

While the sensor was bad, it must have adjusted the mixture rich enough for the old plugs to keep firing... But, when the new sensor was replaced, it must have leaned out the mixture just that much so that the old plugs were just too wide, and creating too much resistance, to do their job any longer.

This leads me to these 2 things: First, NGK Iridiums certainly do have a lifespan, and ought to be checked, and replaced when necessary. And, Two, to whomever I had that pissin' contest with here on the Clinic a couple of months back... I want to extend my most humble apologies to that fellow, and to ask his most gracious forgiveness, as I was just plain WRONG!

I've had the same set in my truck for the last 14 years.
It still runs great.
(Wonder if I could get them out anyways... )

I was just talking to someone who changed his on his 17 year old truck after 140,000 miles. He said the sides were worn, but he went in while chasing a coil and a miss issue.

I know my mileage is the same as it was 13 years ago..

Nothing lasts forever.

I was going to start a new thread about plugs but I'll just ask here....

What's the NGK plug number and gap setting for our bikes ? I have a 2001.
There's good cross reference for oil filters in the tech section but not plugs, unless I overlooked it.

You were giving Davej a 'what fer' on those plugs in the last thread.

BC1955 wrote:
I was going to start a new thread about plugs but I'll just ask here....

What's the NGK plug number and gap setting for our bikes ? I have a 2001.
There's good cross reference for oil filters in the tech section but not plugs, unless I overlooked it.


The NGK # is DPR7EA-9 The Iridium plug # is DPR7EIX-9 The gap is .031-.035 but gaping the Iridium plugs may result in breaking the small center electrode. The center electrode is very fragile and will break if you gap it by prying from it like you can on a regular plug.

Are plugs the same for 1600 and 1700.

Dirty Dan 46 wrote:
Are plugs the same for 1600 and 1700.


Yes same for both

Two things... first of all, everything everywhere says... Do Not Try to Gap Iridium Plugs. Take 'em out of the box, and install them just as they are!

And, Two... Dave, I apologize to you, man. I was totally wrong, and I am sorry. Would you please forgive this stupid brother?

If I knew how to post pics, I'd have loved to have shot a pic of a new plug, right next to what I was pulling out of that Toyota motor, I've got to tell you, the outer electrodes were in hideous condition, and the resulting gap was 'YUGE', as The Donald would say!

davej wrote:
BC1955 wrote:
I was going to start a new thread about plugs but I'll just ask here....

What's the NGK plug number and gap setting for our bikes ? I have a 2001.
There's good cross reference for oil filters in the tech section but not plugs, unless I overlooked it.


The NGK # is DPR7EA-9 The Iridium plug # is DPR7EIX-9 The gap is .031-.035 but gaping the Iridium plugs may result in breaking the small center electrode. The center electrode is very fragile and will break if you gap it by prying from it like you can on a regular plug.

Use the doohickey slot to bend the ground electrode if you must.