Iridium IX plugs - Harley Forum

old no. seven · #1 06-15-2009, 11:20 PM

Here's the bike, 02 FXD w/ 95' BB kit, 203 cams, open intake, open exhaust, and carb. Here's the question for some techs. In the May issue there was a write on the Iridium IX plugs, sounded pretty good. Any thoughts on these plugs?

PeterV · #2 06-16-2009, 03:44 AM

I just got a pair, I wanna see what all the fuss is about.
Let you know in a couple of days.

Gas Man · #3 06-16-2009, 06:24 AM

I had them in my rice rocket back then, when they first came out... they were nice. NGk's set me back at like $15 a piece back then...

evoKENevo · #4 06-16-2009, 11:15 AM

I could'nt find anything in the tables of content of the May issue (if AIM assumed) regarding Iridium IX plugs...but I can tell you all that a spark plug is JUST a freak'n spark plug. No REAL magic there...just a lot of hype between manufacturers.

One of the best articles I've ever come across on what spark plugs DO or DON'T was a two part one by Donnie Peterson in the July & Aug '08 issues. If you have those issues to review I highly recommend you do it. Yeah,and,in the meantime I highly recommend you go to your local Auto Supply to pick up a pair of $2** Champion (all I use) or whatever name brand plugs of the correct size and heat range etc and call it a day...noting the only difference you may find between brands is that their comparable heat ranges (you can cross index) may differ a bit due to slight differences in manufacturing...and a plugs heat range ONLY refers to it's ability to retain or dissipate it's own and combustion chamber temperatures...too cold in a rich running engine they'll foul...and too hot in a lean running engine they'll cause detonation/preigition...nothing more,nothing less...period !!

IMO...buy a pair of correct plugs for $4**and spend the other $26** (out of 30 mentioned here) on a cold case of Premium Beer...

...if you're determined to pee your money away.

Whopper · #5 06-16-2009, 01:26 PM

Ken is right on it!

My first job out of the Army was for a company that made spark plugs. Imagine my shock when we ran our plugs three days per week and then plugs for other name brand manufacturers later in the week. It was not unusual to see a Brand "A" or Brand "C" truck pull up to our dock and unload our brand plugs, boxed and ready for the shelf.

We had a spark plug rating engine ( a variable compression single cylinder engine) that we used to be sure our plugs were in their appropriate heat range and we compared them with Autolite, Champion, AC etc.

No longer fighting weak spark (contact point ignition) or lead fouling (leaded gasoline) plugs of the appropriate heat range will light the fire.

old no. seven · #6 06-16-2009, 08:02 PM

Let me correct the post, May issue of Thunder Press. Article by Kip Woodring. The iridium plugs have a center electrode of .6mm which reduces the voltage requirement to jump the gap and creates a larger spark in relation to a standard plug. The iridium alloy withstands temps up to 4500 degrees F., 700 degrees C. higher than platinum. Seems you can install next cold heat range with no problems and shed a bunch of heat to the cooling fins. Gimmick? Better mouse trap? A couple of the points do make sense, looking for user testimonials. Thanks guys.

frisco-rigid · #7 06-17-2009, 02:10 AM

Hi Old

I have also Never been a believer in spark plug Hype..

If there was REALLY more of anything to be had it would be the Talk of every site, perf mag, radio show, heck it would be on the news..

You know,,,,, alota us guys have used things and experimented with stuff over the years in a search of more power, comfort, mpg, jeeeeze, just about anything you can think of,,,,, well, Now it's your turn..

Go get a set,, you know you want to, record all the Mpg gains and power gains and temp diff Before & After and heck, Buzz just might publish your research/story in AIM mag..

I am Not being sarcastic Old, really,,,, do it and report back to us all if they are worth a flying forni.......

I just put a new set of N12YC's in our sickles and there is a slight percieved boost, ah, you know, replacing 2 year old plugs with New always seems to feel better..

old no. seven · #8 06-17-2009, 09:43 AM

Hey Frisco , just planting a seed here for Buzz or maybe Chris to follow up on this. They have the resources to check this out. I showed the article to the service manager at the HD dealer I frequent, he is a former NHRA Drag bike racer and knows Kip Woodring, seems to have peaked his curiosity also. Yea I'll probably get a set, more for the engine internal benefits, stuff I won't see. Thanks for the inputs. Ride safe.

PeterV · #9 06-19-2009, 09:55 PM

Seat of the pants feel after 3 days of riding.
Smoother.
Motor runs smoother.
That's it.
If these were selling for $4 a piece, yep...I'd keep on using them.
For the price they're asking? First and last time I buy them.
Sooo, there ya have it!

Pete

PeterV · #10 09-08-2009, 01:44 PM

Well!! Who'd have thunk?...

Almost three months (and 5k kms) later and the picture has changed considerably.
Cooler. Yep, these suckers run cooler. 15F cooler is nothing to sneeze at. And...

My friggin gas mileage has gone UP. Considerably.
I have never been able to better my gas mileage over 275kms (which imho is pretty good.. DJ carb kit, SE air, Andrews 26G, SE ignition, Kerkers with Mikuni baffles)
Since I put the iridiums in, I have refrained playing with the carb.
2 weeks after running these plugs I'm at 305kms as I flip over to reserve.
That's 30kms more per tank. 20mpg.

Lesson learned. Keep mouth shut a little longer than 3 days before forming an opinion...