Iridium spark plug are NOT forever..

[TownsendsFJR1300]

Long story short.

I've been chasing a vib, very high frequency,definitly engine RPM related.

After many checks, adjustments, re-setting engine position-torque, sync, etc, I found the issue...

After doing a spark plug wire shortening(didn't need it, no arcing, two slightly loose) I checked the
spark plugs.

Two were about finger tight, the two maybe 5' lbs holding them in. Pulled the NGK Iridiums
which had a decent color, and checked the gaps. When initially installed 12,000 miles ago, they were
at .027-.028". Now, they were at .032", .033", .034" and ,034.5"

Picked up some new ones, re-gapped (only one was at .028") the rest were about 030", .031"
and re-assembled... No more de-cel vibs thru the seat, and rt foot peg, noticeably smoother, back to
normal... (that's a Big SMILE)


Plugs were the last thing (especially Iridiums) I thought would be the issue but in fact,
they DO NOT LAST indefinitely. Count on changing them pretty much as you would the stock plugs..

As far as I'm concerned, they get R&Red every 12K miles. Just something to pay attention to for maintenance
and / or running issues..

 

[FinalImpact]

Once again the value in verifying and getting the facts!

As owners of these bikes and with so many saying they are a buzzbomb, well the buzz is in the details. I have suggested repeatedly that these bikes need balance and equal firing energy at all plugs for them to be smooth. Once again, proof that tiny details can matter!

These being waste spark and high revving means the ignition spark being delivered at the right time matters! Imbalance like plug gap or resistance in the two outputs of the same coil means spark time, if off just a little induces vibes into the crankshfts firing sequence. This creates the harmonic vibes we feel.

I'm glad you found the source of the vibes. And although the original source for them is unrelated to what you found, its just another reason to stay on task with the manufacturers recommend intervals...

Being waste spark means they are fired 2X more than COP engine. Having a rev range over 10k, means more wear per minute than lower reving engines...

Glad bike and rider are happy again!

 

[VEGASRIDER]

I got over 50k miles om my Iridium, only reason why they were replaced was because it was convenient to do so at the time my valve checks were being performed.

 

[TownsendsFJR1300]

I got over 50k miles om my Iridium, only reason why they were replaced was because it was convenient to do so at the time my valve checks were being performed.

The bike still ran fine BUT, I had these vibs all of a sudden after a 0 MPH tip over(engine NOT running).
It must have just been coincidence. It had ALL the symptoms of the loose coil /spark plug wires which
were checked...

Both FI and I believed it was in the ignition somewhere (I was fixing to order new coils from Skooter65).

I just happened to check them while in there this am... They may go longer BUT IME, they don't last
longer than OEM plugs / or perform 100% in that period.

Perhaps a tighter plug gap would last longer... But they definitely don't last longer than the OEMs..

 

[VEGASRIDER]

There was one thread in which the Iridium plugs caused poor MPG. That was the only negative thing I've heard about them until this post. I know I got over 20k miles on my OEM stock plugs, and same thing, only changed them not because they failed, but because I wanted too. I think the manual says every 8000 miles.

 

[TownsendsFJR1300]

I had 10K on my original plugs which looked fine with no vibs...

I just changed them for the mileage and the belief that the Iridiums would be the last time.

I really didn't notice ANY difference, mileage, performance, nothing between stock and iridiums.

I'll probably go back to OEMs after 8,000 miles on these...


*As a side note, I have a Yamaha outboard engine, F150, 4 stroke, 150 HP, 4 banger, 2300cc.
I had running issues (bogging) at 5,300 RPMs last year. WOT is normally 6,000. (My boat
would run 5,900 RPM's @ WOT trimmed out).
Long story short, original plugs (200 hours) were replaced, problem SOLVED.

Point being, basic's, spark plugs are an integral part of your engine and are often
skipped (myself included)...


.

 

[aussiejules]

Quick note platnum and iridium plugs should not be gapped or checked, in doing so you can/will damage the thin coating on the plugs. I tell all my customers if they go near them with feeler gauges you might as well throw them away.

 

[Motogiro]

The manufacturer (NGK) does recommend the proper gap,for Iridium plugs, called out by the vehicle manufacturer.
If you look at the tip of the electrode you'll see a tiny piece of Iridium, laser welded the the anode. This is not plating as used on platinum plated plugs.
Use the proper tool and procedure, being careful not to break the iridium off the anode.

Spark is effected by compression, temperature, chemical composition of it's environment and of course voltage.

[video=youtube;lk70oyUEftY]https://www.youtube.com/watch?v=lk70oyUEftY[/video]

Here's another interesting video.


[video=youtube;w962iS-7ELQ]https://www.youtube.com/watch?v=w962iS-7ELQ[/video]

 

[FinalImpact]

I think we've played these games before...

• Can OEM plugs last more than 12k - Yes!
• Are they worn and opening up the gap - Yes!
• Are all bikes affected the same by worn plugs - No!
• Is it wise to question the inexpensive wearing components when there are performance issues - Yes!!!
• Can precious metal plugs be gapped using the right tools safely - Yes!!!!
• Should all new/used plugs be checked and set to the correct specification BEFORE installing them - YES!!!!

 

[FinalImpact]

Exhibits A & B at 13,000 miles...

Notice wear on both sides of the electrode

Gap is beyond spec at 13k...

CR9E after 10K mi gap is in spec

CR10E @3000 mi after S1 header, ignition advance, Bazzaz ZFI tuner....

 

[TownsendsFJR1300]

Quick note platnum and iridium plugs should not be gapped or checked, in doing so you can/will damage the thin coating on the plugs. I tell all my customers if they go near them with feeler gauges you might as well throw them away.

This is NOT true.

Per NGK tech and their website they should.

The round "wire style" gauge should be used, no flat gauges...

They should NOT be tapped down to tighten the gap but use the proper tool to adjust the ground strap, tighter or looser.

Adjusting in this manner will not touch or hurt the electrode or tip...

These and most plugs are used for various machines and the gaps different for each.

Do NOT install the plugs without checking / adjusting PROPERLY

 

[IanHoots]

You may be interested that I have experienced something similar with an EJ20T engine. It can in idling badly/rough/vibrating, however ran well at all other times. I had carried out all the maintenance to spec and believed the owners were not overly aggressive drivers. It turned out to not have carbon build up in the inlet or piston crowns. The root problem was iridium plug (that I had installed 45,000klm previous) were gappy, but looked OK other than gap. I replaced them (which is a b1tch of a job) and the problem disappeared.

 

[bpchura]

Could someone clear something up for me? I would imagine that to a point, a plug could technically just be regapped when worn? Obviously to a point and barring fouled, damaged, and very worn plugs, the wear is just the change in the gap right? Its not a huge deal to change them out and replace but after 12k, couldn't you just regap? Just wondering, thanks!

 

[Motogiro]

Could someone clear something up for me? I would imagine that to a point, a plug could technically just be regapped when worn? Obviously to a point and barring fouled, damaged, and very worn plugs, the wear is just the change in the gap right? Its not a huge deal to change them out and replace but after 12k, couldn't you just regap? Just wondering, thanks!

An excellent question! One thing I think I would change them for is the new crush washer they come with. Although I've changed many plugs I like fresh properly gapped plugs. I've seen people sand blast them regap and reinstall. As long as you're sure there is no debris afterward and there is no heavy loss of material they should be okay.

 

[aussiejules]

Technical information

Electrode Gap Adjustment

NGK do not recommend gap adjustment for precious metal spark plugs.

A variety of techniques are used to adjust electrode gaps. An appropriate method and tool should be used for gap adjustment although it has come to our attention that a variety of improper methods are used that lead to implications.

When adjusting the electrode gap, the gap may commonly be made too small, as such, the gap may need to be opened slightly. Typically some customers use a lever such as a flat screwdriver to pry open the gap. Traditional Nickel plugs have a solid piece Ø2.5mm centre electrode that may withstand such force. Precious metal spark plugs however have Ø0.6mm fine tips that are laser welded to the centre electrode. These tips are very fragile and not designed to withstand any force. As such NGK will not provide warranty for the breakage of precious metal centre electrode tips.

It is possible to adjust the electrode gap on precious metal spark plugs using an appropriate method that will not place any force on the centre electrode tip.

Sorry i obviously got the wrong idea from this tech information from NGK.

 

[TownsendsFJR1300]

Glad that's cleared up, ^^^.

They used to have a section that clearly addressed the adjustment of iridium plugs (yea or nay).
That section is now gone, thus the confusion. There is info about using the correct tool,
NOT smacking the ground strap(which is why I called) to tighten / adjust the gap.

For anyone with questions re gapping, a quick call to their tech department will clear things up.

Re my much larger gap over time, I did call NGK and spoke with tech. I inquired specifically about simply
closing the gap. He said YES, it can be done, but the plugs were simply worn and should be replaced.

He also stated to gap them the same # as the stock plug, no more, no less..

**Also, somewhat new (at least to me), they do NOT recommend adjustment of ANY PLUG more than .008"..
So with my my old plugs widest gap at .034", I could bring it back to .026", the middle of spec.

 

[IanHoots]

NGK also deters you from sand blasting a precious metal plug. I've read somewhere it can encourage the tip to detach from the electrode. I'm not game enough to test their theory, as a plug failure could be a disaster. New plugs is cheap insurance.

 

[FinalImpact]

If your engine is burning clean, there is no need to sand blast anything.

i.e. correct AFR, proper compression, valve guides in good shape, and the correct heat range of spark plug that stays hot enough to burn off the deposits created during combustion, but not so hot as to soften and melt components.
That said, even a perfect setup can be fouled up by treating it like a tractor engine and lugging it around. They like to rev so let them! It keeps the combustion chamber clean and chemicals are not required for maintenance.

Nothing against precious metal plugs (they have their place) but I'd rather look and know the health of things through inspection. 15" of time is not huge deal to remove them.

 

[TownsendsFJR1300]

Just an update to my vib's which the new plugs did NOT fully fix:

http://www.600riders.com/forum/fz6-technical/57056-high-frequency-seat-vibrations-eliminated.html

The rear sub-frame apparently shifted some when the bike fell over. Loosening fully, all the 4 sub-frame bolts
and re-torquing fixed ALL the remaining high frequency vibs(especially thru the seat.)

 

[Pittmania]

So....what spark plugs should I replace my OEM ones with?