Let's talk iridium plugs

[thepittsburghguzzi]

No screaming, yelling, name-calling, lamp-throwing, knuckle-busting here.

But give me some recent experiences with iridium plugs (namely on a V7 Classic, if any of you folks have tried). Plugs seem to be like oil - everyone has a different opinion, often a strong one, and I'll probably just end up trying iridium plugs to see if I like them or not.

In the meantime, let's have some personal anecdotes and see if I can make an even more educated decision. Thanks friends!

 

[oldbike54]

 Why you little (bleeped) , you should be (bleeped) ashamed of your (bleeped) self for asking such a (bleeped) question on Saturday morning and (bleeped) my morning  HMMFFP , (bleeped) troublemaker . What the (BLEEP) ????

 Seriously , don't they cost like $500.00 a piece ?

  Dusty

[thepittsburghguzzi]

They only retail for $12 for the BR8EIX plug 

I've seen them on amazon for $8 

[Dilliw]

Leafman posted that he had good results from the Denso iridiums in his Stelvio.  I've got a set on the bench for when the Griso comes back from being rolled.  $8.50 each.

http://wildguzzi.com/forum/index.php?topic=70882.0

[Old Jock]

Got them in the LM 1000.

Nippon Denso

So far they have been great, could be my imagination but you seem to get a fatter spark

Here in the UK they are pricey but nowhere like $500 more like $30-40

[Perazzimx14]

I've put them in both of my DR650's and they seem to perform no differently that the stock plugs they replaced. At $6.99 per I don't think they were a waste of money but they are also not panacea.

[canuguzzi]

http://wildguzzi.com/forum/index.php?topic=76976.0

A quick search for Iridium at the top right brings up lots of info about this, some of it recent.

[guzzisteve]

The only model they don't work in is a 2012 V7

[redrider]

I have used regular flavor plugs in everything for decades. The old days of having the "wasted spark" had the plug also fire on the exhaust stroke. Purportedly to reduce fouling and ignite any residual mix for emissions compliance. (Hogwash imo) It was,IMO a way for one coil to fire two cylinders in the I4 UJM. Problem-plugs only lasted 1/2 at best of the same plug in a distributor design. Plug fires and a small amount of materiel is vaporized for the sake of ignition and the gap widens with age. Special materials mean less wear according to those who sell special things. Spark depends on voltage delivered which allows wider gap and more exposure to the mix with higher voltage. Guzziology covers the issue well. Fancy=snakeoil my 2c

[sib]

My 2004 Prius came with iridium plugs and I like the fact that they're supposed to last for 120,000 miles and they actually did last that long.  They are not claimed to work any better than standard plugs, give more horsepower, or better fuel mileage, etc..  For motorcycles, we riders tend to be the sorts who cannot leave well enough alone, and I doubt that any of us would not replace spark plugs more often than that.  If you are going to be constantly fiddling with your bike and changing spark plugs frequently anyway, it seems to me that iridium plugs are a waste of money.

[jcctx]

The "thin wire" plugs sure helped with the old 2-strokes when first available. Not so sure with modern 4-strokers and lead free fuel!!

[ChuckH]

Spark plugs wear out during normal operation because the gap increases (erodes) and the electrical system (coil, wires, etc) can not jump the larger gap.  The iridium plugs (I've also seen platinum used) have an iridium electrode.  That material erodes at a slower rate. 

Iridium costs more than the steel material normally used for the electrode, so the cost of the plug is higher.  The operation of the engine is not going to be different, regardless of the plug that is used.  The only difference is that the plug with the precious metal electrode will have a longer useable life.  It really is a cost/benefit decision -- does the higher cost of the iridium plug give you enough longer life to justify the higher price?

Ride safe.

[Dilliw]

Spark plugs wear out during normal operation because the gap increases (erodes) and the electrical system (coil, wires, etc) can not jump the larger gap.  The iridium plugs (I've also seen platinum used) have an iridium electrode.  That material erodes at a slower rate. 

Iridium costs more than the steel material normally used for the electrode, so the cost of the plug is higher.  The operation of the engine is not going to be different, regardless of the plug that is used.  The only difference is that the plug with the precious metal electrode will have a longer useable life.  It really is a cost/benefit decision -- does the higher cost of the iridium plug give you enough longer life to justify the higher price?

Ride safe.

Yeh I agree that iridium is not, by itself, going to help a motor run better; it will make it run the same longer.  But I can also say with certainty that some plugs work better than others in a particular application.  Leafman said that those Denso's made his bike stumble less at lower rpms and I figure it's worth the shot to try them as my bike doesn't like 3k and below.  It could be they work well in the application regardless of the material.

[clubman]

Used them in my V7C almost since new and really like them. You won't notice any difference in performance, but they wear practically forever. Have a set in my Triumph with nearly 40K miles and still runs like new. I buy from sparkplugs.com for a better price.

[Chuck in Indiana]

Brad and I were in the pits helping (hindering)  Jim Barron of Rose Farm, and he handed the Kid a couple of iridium plugs to put in the race bike. He winked, grinned and said, "the owner believes in them, but they won't make it run a bit better.." He also said when he pulls a plug from a bike that's in for service, it gets a new one. Many subtle problems are caused by plugs, and they are so cheap it makes sense for him to do that.

[canuguzzi]

I'll jump in (throw me a life preserver).

Iridium and platinum were only developed by auto manufacturers to extend the time between required services and use that as a marketing ploy.  Neither one conducts as well as an old fashioned copper plug.  The multi-electrode plugs are also a marketing ploy.  Electricity is going to take the path of least resistance to get to a ground.  Only one of the electrodes will ever get used.  The electrode on copper plugs erodes quickly, so the plugs need attention every few thousand miles and they probably need replacing at about 10k.  That's just too much for some people, so they get out their wallets.  Platinum plugs are probably a happy medium.

BTW, do not attempt to gap platinum or iridium plugs.  Both have platinum coated ground electrodes (the part you bend to set the gap).  The platinum will crack when you bend the electrode and eventually fail and flake off.

 

[Rough Edge racing]

I'll jump in (throw me a life preserver).

Iridium and platinum were only developed by auto manufacturers to extend the time between required services and use that as a marketing ploy.  Neither one conducts as well as an old fashioned copper plug.  The multi-electrode plugs are also a marketing ploy.  Electricity is going to take the path of least resistance to get to a ground.  Only one of the electrodes will ever get used.  The electrode on copper plugs erodes quickly, so the plugs need attention every few thousand miles and they probably need replacing at about 10k.  That's just too much for some people, so they get out their wallets.  Platinum plugs are probably a happy medium.

BTW, do not attempt to gap platinum or iridium plugs.  Both have platinum coated ground electrodes (the part you bend to set the gap).  The platinum will crack when you bend the electrode and eventually fail and flake off.

   From my experience, standard type spark plugs can last 20,000 miles in some modern engines with no decrease in performance. On many newer vehicles changing plugs is a major project and a long life plug is a labor saver.....Unless it seizes in place from being in the engine for 100K miles...
   I use NGK "G" fine wire spark plugs on my vintage Triumph race bikes. They are replaced after about 4 runs down the 1-1/2 mile track...Not because of wear but potential  fouling because of high tetra-ethyl lead content in the racing gas

[sign216]

As for standard plugs, I found using an extra-reach plug in my Gilera 106 single let me adjust the idle nice and low. 
Getting the spark further into the combustion chamber was a big help at low speeds and it idles beautifully now.

[ITSec]

My 2v Norge has platinum plugs (moderate price) for the outer units (easily changed), and iridium plugs (not cheap, but not that bad) for the inner, hard to reach ones. I change the outer ones about every 20,000 miles, and the inner ones after about 40,000 - but not until I have another reason to pull the airbox!

As has been noted, the benefit is how long they last, not how well they work. Since the Norge is used for long-distance riding and gets around 25 to 30K a year (unless I'm sick or broke), I always opt for whatever extends my service intervals without compromising reliability.

[Waltr]

  I will not longer pay double for exotic plugs for my Norge.  The recommended replacement interval is 6750 miles and the bike runs better with fresh plugs. The Denso iridium's do work and last longer well but even they seem to run better fresh. 

[ITSec]

  I will not longer pay double for exotic plugs for my Norge.  The recommended replacement interval is 6750 miles and the bike runs better with fresh plugs. The Denso iridium's do work and last longer well but even they seem to run better fresh.

But unless I'm mistaken, the newer motor has two plugs, not four - and they are placed where you can easily change them (other than the plug boot question). I might go with you given that difference, though I'd still likely pay the small uplift for platinum. I've seldom noticed any difference when replacing plugs on any bike other than my RD400 back in the day...

[RANDM]

My R1150R is 'sposed to have the two earth plugs which one
BMW shop wanted to charge me $37Au a pair for. I looked
around and got that down to $27Au a pair but while looking
I found Iridium equivalents in Ireland that I could get for $27
When they hit my letterbox - guess what I did.
The bike has a wasted spark system, changed the original
type around every third oil change - 15,000klms.
Iridiums have been in for 8 - 10,000 now, no real measurable
performance difference that I can feel. Guess I'll find out if
they do last longer soon, but even if they don't I'm satisfied
'Cause I didn't pay a rip off price for the essentially normal
plug and if the experiment fails will get the normal plug OS
for 1/2 the Au price in future.

Maurie.

[injundave]

My wife's car is a 1999 Nissan Maxima 3.0 litre V6. It has done 250,000 km (about 166,000 miles) and is on its second set of plugs. Iridium plugs are specified by the manufacturer. I'm real glad they last so long because they are buggers to get out.

[flangeman_70]

I run Iridium in both my Guzzi's and for good reason. Longevity, heat, detonation control and anti fouling properties(SPIII).
Both bikes have high powered ignition systems (Basically any machine with a digital ignition is considered high power). Older style nickel alloy plugs will erode the centre electrode away quickly. The SPIII fires every crank revolution with the Sachse ZDG3 ignition and uses bobbin style coils. It eats conventional plugs in a matter of a couple thousand kms. My last set of Iridiums did 30K before I screwed one up with a worn out valve guide and worn rings.

There is a lot of physics that goes into design and use of spark plugs, amongst other things, and there are plenty of sources out there with good info on why and how. Here is a good read http://shop.advanceautoparts.com/o/article-spark-plug-basics

Good luck

Adam