Topic: Iridium spark plugs. Fact or Fiction?

[KC_Northstar]

I'm seeing all kinds of claims about iridium spark plugs being better
and making more horse power than standard plugs.  Anyone know
if these claims are valid?  I don't believe the claims, but I'm no
expert.

KC
 

[K5owner]

Iridium spark plugs have been OEM for many automotive manufacturers for a few years. This is how they claim 100k miles "between tune-ups". I used them when I had to replace the plugs in my 1997 Valkyrie, and didn't see any improvement in performance or fuel economy. I didn't have the bike that long to know if the plugs lasted longer.

As a side note; I did replace the iridium plugs in my Ridgeline at 100k and they could have gone another 20k without a problem.

[lucky]

I'm seeing all kinds of claims about iridium spark plugs being better
and making more horse power than standard plugs.  Anyone know
if these claims are valid?  I don't believe the claims, but I'm no
expert.

KC

They have been around for a long time.
Just like the platinum plug, the most important feature is that the electrode is very small in diameter as opposed to a conventional spark plug.

They even used to be called "fine wire plugs"
Since the electrode diameter was very small it offered less resistance.
But the electrode had to stand up to the heat and compression the engine would dish out.

[Really?]

I have used the gold tipped plugs loooong ago and I did feel a difference in both bike and car with them.  Small but I felt it.

[Rgconner]

I'm seeing all kinds of claims about iridium spark plugs being better
and making more horse power than standard plugs.  Anyone know
if these claims are valid?  I don't believe the claims, but I'm no
expert.

KC

They have been around for a long time.
Just like the platinum plug, the most important feature is that the electrode is very small in diameter as opposed to a conventional spark plug.

They even used to be called "fine wire plugs"
Since the electrode diameter was very small it offered less resistance.
But the electrode had to stand up to the heat and compression the engine would dish out.

Resistance goes up as diameter goes down.

[Scott S]

 They work really well in my XS650. Haven't tried them in a SOHC4 yet.

[nancy]

Had them, came with the bike from PO. two of them died one by one and I replaced them with regular types for a quarter of the price. The bike goes no differently now with 4 x regulars. So,..why pay 4 times as much? Dunno.
Regards
Mark

[chewbacca5000]

If your engine is in tune you probably won't notice too much of a difference.  If your timing is a little off it may help compensate.  I have used them and sometimes it seems to perk things up, and others nothing.  Having a good engine tune is probably the biggest thing.

What are you trying to accomplish?  More power, better fuel etc..

[Sam Green Racing]

FACT, the average biker won't notice the diference but put them in a well set up motor and stick it on the dyno and you will see the difference.
Starting is much easier and you can come off choke quicker.
I think we picked up a 10th over the quarter mile.

Sam.

[400f newbie]

  my 400f ran very well but never started too easy.after fitting iridium with no other mods i was able to start with one or two kicks.     i also found that i could shut off choke a lot sooner,     i can not tell if there is a power increase but the ease of starting was worth the extra $20.      ray.                       

[becken]

http://www.ngksparkplugs.com/docs/tech/Precious_Metal%20_PlugsPowerSport.pdf

[scunny]

had a race sorted GS1000 back in the day and on the road it ate spark plugs for breakfast. put in a set of platinum plugs on recommendation of the engine tuner and end of problem.

[lone*X]

My 03 VTX1800 came with iridiums factory.  Can't compare them to anything else in the X but I can say the last a loooong time.  Still running the originals and thats about 40K miles.  I checked them about 2K miles ago while servicing the bike.  Still look and perform like new.

[CoachDoc]

Some of the iridium plugs come only as resistor plugs, which could be a problem if used with resistor caps. It would be smart to find non-resistor caps in this situation.

[Danno]

my 750 A had irridium plugs in it and it never ran right with them as pointed out on some modern vehicles like my truck it uses laser cut irridium plugs and they go for about 80k before needing changed but on a bike with all the accell and decell they will still carbon up and wear out i would not waste the money on them i use standard NGK plugs but they are also the ones that make my laser cut plugs as well