Irridium Spark Plugs

[3dogs]

After replacing old spark plugs with new, many riders experience engine performance gains including; smoother running, better idle quality, easier starting, better fuel mileage, quicker gear changes, longer battery life and a general increase in horsepower. I have found that after 40+ years of riding and working on motorcycles that there are two primary factors that make a difference in engine performance with regards to spark plugs.

1) Price. The more expensive, or hard to obtain, the new spark plugs are the greater the engine performance.

2) Level of Effort. The other factor that is at least equal to, or greater than number 1, is the amount of effort it takes to change the spark plugs. If the job takes hours to accomplish and lots of body work has to be removed to gain access to the plugs the better the engine runs when the job is done—it’s amazing. And if one strips threads or breaks a fastener during the spark plug changing process the engine performance gains can potentially be even greater.

I used to own/work on lots Harleys and I think that the spark plug/engine performance phenomena is directly related to replacing stock ignition systems on a Harley-Davidson with a “high-performance” ignition and ignition wires. After spending $500 on the ignition system, and another $200 at the dealer to get it installed, any low compression, low revving V-45 engine feels a lot stronger when accelerating—it’s true—just ask any rider that has had this mod done to their bike! Fortunately FJR and other Japanese motorcycle owners can benefit from a simple spark plug change in the same way.

 

[ionbeam]

After replacing old spark plugs with new, many riders experience engine performance gains including; smoother running, better idle quality, easier starting, better fuel mileage, quicker gear changes, longer battery life and a general increase in horsepower...The more expensive, or hard to obtain, the new spark plugs are the greater the engine performance...If the job takes hours to accomplish and lots of body work has to be removed to gain access to the plugs the better the engine runs when the job is done...performance phenomena is directly related to replacing stock ignition systems on a Harley-Davidson with a “high-performance” ignition and ignition wires...

That is one of the best explanations I've read about spark plug replacement! I think you have hit all the important cost/benefit results. The only thing I might add is if you want even better results try running premium gas. Even better, if you can get leaded racing gas your bike's performance will move into a whole new level.

 

[Warchild]

Only half of your cylinders are enjoying the renewed vigor of iridium.
Clicketh

Warchild

Jun 16 2009, 11:50 AM

Post #2

{snippity do-dah}

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- Warchild

FJRForum.com Benevolent Dictator

https://www.FJRTech.com/

[SIZE=14pt]Yea, see this is what I was speaking about........Bike is at 16.5k..............I just rejuiced the engine with fresh plugs - I suppose any would have done; but I got the irridiums.......so THERE![/SIZE]

Sorry, RemingtonRider, you have completely misinterpreted what I wrote.

I am not referring to 16K-17K on the engine; I am referring to 16K-17K on the same set of Iridium plugs.... this is the mileage amount when the iridiums start to noticeably deteriorate.

That is to say: comparing the observed performance on the two types of spark plugs: at ~ 10K miles (on the plugs, not the engine) the copper NGKs fall off noticeably compared to the iridiums. At ~ 16-17K miles (on the plugs, not the engine) the iridiums start to head south themselves, and become candidates for replacement.

Bottom line: it is, as many posts in this thread suggest, your imagination. When brand new, there is no appreciable difference in performance between the two types of plugs. The advantage of the iridiums is longevity.... they perform well much *longer* than the copper NGKs, is all.

 

[FJR-RemingtonRider]

Oh bro's.....I get it

I agree with the assessments made by all in previous threads.

Since I have put 6k miles on the bike, it was at 10k when I purchased it. So conceivably the spark plugs have never been changed.....ergo 16.5k ( I really don't know)

If they were it was maybe at recommended 8k or sooner.

So the gains I am experiencing/ performance and all is from the fact that the Denso plugs were at the end or beyond their life-cycle.

Any fresh plug would have produced the results I have now.......So I can look foward enjoying these irridiums far longer than the others...I like that.

 

[Fred W]

Remington,

If you removed Denso plugs then they were not stock. The stock plugs were NGK copper core CR8E's.

FWIW - (one data point) My original set of stock plugs didn't come out until 16k miles and I could detect no improvement in the way the engine ran. I therefore see no economy in buying the CR8EIX plugs at twice the price. YMMV.

PS - iridium is spelled with just one r.

 

[charismaticmegafauna]

If you removed Denso plugs then they were not stock. The stock plugs were NGK copper core CR8E's.

While your stock sparkplugs were NGKs, it may not follow that all stock installs were?

The FSM lists both NGK CR8E and ND (Denso) U24ESR-N as OEM fitments.

I've seen many new machines with NDs installed as 'original'.

I guess, without a sizeable statisical sample (member poll), we can't assume that 'Remington's (original fitments) were not NDs. :blink: :huh:

 

[RadioHowie]

I guess, without a sizeable statisical sample (member poll), we can't assume that 'Remington's (original fitments) were not NDs. :blink: :huh:

PM SkooterG....that cheap bastie's prolly still running the originals, even at 200+K miles.

 

[Fred W]

If you removed Denso plugs then they were not stock. The stock plugs were NGK copper core CR8E's.

While your stock sparkplugs were NGKs, it may not follow that all stock installs were?

The FSM lists both NGK CR8E and ND (Denso) U24ESR-N as OEM fitments.

I've seen many new machines with NDs installed as 'original'.

I guess, without a sizeable statisical sample (member poll), we can't assume that 'Remington's (original fitments) were not NDs. :blink: :huh:

You know, I thought of that before I posted. And I know what you mean, I have heard of other bikes coming with Denso's, I've just never heard anyone say their FJR did, so i ***-u-med they only came with NGKs. I will open a poll forthwith and we shall get to the bottom of this most important question!!

Hey... it's winter. :glare:

 

[UHOH]

I have found that after 40+ years of riding and working on motorcycles that there are two primary factors that make a difference in engine performance with regards to spark plugs.
1) Price. The more expensive ... the greater the engine performance.

2) Level of Effort. The other factor that is at least equal to, or greater than number 1, is the amount of effort it takes to change the spark plugs. If the job takes hours to accomplish and lots of body work has to be removed to gain access to the plugs the better the engine runs when the job is done—it’s amazing.

Experience speaks ^^^, listen.

Some yrs ago had changed my stock plugs @ 12,500 miles (looked good) for iridium plugs. couldn't notice any difference.

still use iridium plugs now (@52,000 miles). Now can't even remember when I changed them last. My bad.

so the benefit is in our heads, unless dyno testing shows us otherwise...which hasn't been presented.

 

[UselessPickles]

so the benefit is in our heads, unless dyno testing shows us otherwise...which hasn't been presented.

Someone actually did do some spark plug dyno comparisons. It was with a Dodge Neon SRT4, but I wouldn't be surprised if the same general pattern of results applied to the FJR also: https://www.sparkplugs.com/sparkplug411.asp...ults&mfid=0

The short version is that they did 3 different dyno runs with each spark plug type: cold engine, warm engine and hot (heat soaked) engine. The Iridiums performed the most consistently among the different runs (almost identical) and were pretty close to having the highest average numbers between the 3 runs.

 

[Bluestreek]

I had 55k miles on the plugs that came from the factory when I switched to Iridiums and if there's any difference my butt dyno was unable to detect it. Fuel milage remains the same.

The next plug change will be back to the OEM spec.

 

[FantasticJohnR]

Sounds like the wires that pulled loose when changing the plugs was loose from the start and may be the reason for your hard starts previously- someone else migh have already posted this- but I was too lazy to read through all the previous posts :w00t: