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View Full Version : Spark plugs: Iridium vs stock


reconstyle
02-14-2007, 09:45 PM
Anyone have any suggestions on spark plugs for an 05 600? Anyone see some pros or cons in the iridiums? Does it really make a difference? I am running an Ivan's jet kit and a yosh rs3 exhaust, what would be the best choice for me?

md86
02-15-2007, 03:04 AM
Stock NGK will be JUST fine .

katman05
02-15-2007, 07:43 AM
I thought I'd give the Iridium a try this time, you can get both from Cyber http://www.katriders.com/forums/viewtopic.php?t=17251

katman05
02-15-2007, 08:23 AM
Here's an NGK link http://www.ngksparkplugs.com/products/spark_plugs/index.asp?mode=nml

The CyberPoet
02-16-2007, 02:22 AM
Here's what you need to know:

If your old plugs are in perfect health, based on your riding habits and carb settings, you won't get any benefit out of the Irridiums -- save your money (note that I only get $4 extra for a set of four irridiums than 4 stock ngk plugs for the 98+).

All modern spark plugs act like a self-cleaning oven, burning off fouling (in the NGK's case from about 500 degrees C to about 850 degree C). As long as your carbs don't foul the plugs before they can reach 500 degrees, and the engine doesn't over-cook them (taking them above 850), stock plugs are fine.

The irridium's design heats the tip a bit faster and it has a 50 degree wider burn-off range (about 450 - 875 degrees), meaning it's somewhat less prone to fouling at the extremes of the temp ranges.

The three times that it's really beneficial to use irridiums instead are:
1. For those who tend to ride short distances (like some whose daily run is a 1 mile ride to school & back), where the engine never gets up to full operating temp. It may or may not make the difference, depending on whether your bike is hitting that 450 degree mark (if the ride is too short to hit 450, get an advancer, stick with OEM jetting, and/or take the long way home from class);
2. Those who need to run the choke heavily to get the bike started (because of very cold ambient temps or lean settings) -- choke use loads up fouling very quickly. AND
3. Those who have particularly rich or lean mixtures. Ivan's can qualify under this, since his kit hits a 13:1 fuel-air ratio once off-idle, but as long as you get in at least a good 10 - 15 miles per ride, it shouldn't be an issue. Running an advancer will also help get the plugs up to temp quicker (but it's a trade off, because they'll load with more fouling under choke use).

Personally, I run the irridiums on my bike with the Ivan's kit just to help be on the safe side. 90% of my riding is long-range (30-600 miles), but that other 10% where I just run over to blockbuster, the local bank, etc., is what prefer the irridiums for my needs.

Cheers,
=-= The CyberPoet

reconstyle
02-16-2007, 09:43 AM
Awesome, very well explained....as usual, thanks

Jax
02-16-2007, 11:12 AM
I've been running Iridiums in my bike for the past year and really like them...I fall under the 1st definition of Cybers reasons to use them...my trip to work is only 5 miles...6 if I take the long way, which in the summer is normal...I like them and they seem to work for me better than the stock...although my bike is running better since I found a competent mechanic that really fixed my bike this time...

IForgotMyUserName2
05-04-2007, 10:17 AM
Here's what you need to know:

If your old plugs are in perfect health, based on your riding habits and carb settings, you won't get any benefit out of the Irridiums -- save your money (note that I only get $4 extra for a set of four irridiums than 4 stock ngk plugs for the 98+).

All modern spark plugs act like a self-cleaning oven, burning off fouling (in the NGK's case from about 500 degrees C to about 850 degree C). As long as your carbs don't foul the plugs before they can reach 500 degrees, and the engine doesn't over-cook them (taking them above 850), stock plugs are fine.

The irridium's design heats the tip a bit faster and it has a 50 degree wider burn-off range (about 450 - 875 degrees), meaning it's somewhat less prone to fouling at the extremes of the temp ranges.

The three times that it's really beneficial to use irridiums instead are:
1. For those who tend to ride short distances (like some whose daily run is a 1 mile ride to school & back), where the engine never gets up to full operating temp. It may or may not make the difference, depending on whether your bike is hitting that 450 degree mark (if the ride is too short to hit 450, get an advancer, stick with OEM jetting, and/or take the long way home from class);
2. Those who need to run the choke heavily to get the bike started (because of very cold ambient temps or lean settings) -- choke use loads up fouling very quickly. AND
3. Those who have particularly rich or lean mixtures. Ivan's can qualify under this, since his kit hits a 13:1 fuel-air ratio once off-idle, but as long as you get in at least a good 10 - 15 miles per ride, it shouldn't be an issue. Running an advancer will also help get the plugs up to temp quicker (but it's a trade off, because they'll load with more fouling under choke use).

Personally, I run the irridiums on my bike with the Ivan's kit just to help be on the safe side. 90% of my riding is long-range (30-600 miles), but that other 10% where I just run over to blockbuster, the local bank, etc., is what prefer the irridiums for my needs.

Cheers,
=-= The CyberPoet


CYBERPOET.... you are the friggin man. after readin this im gonna go with the stock, i dont see why i would need the iridium, all of my riding is always at least 10-15 miles unless i run down the street to a buddies house but thats rare. THANKS FOR THE INFO!

jasmail
05-04-2007, 03:07 PM
I have used the irridium plugs in my last three bikes because of the increased throttle response and smooth excelleration.

My setups have all been the same(except my Katana):
-K&N Filter
-Stage 1 Jet kit
-Free flowing exhaust

On my Katana the irridium plugs did exactly the same thing and it is stock.
I have since drilled the silencer in my exhaust and have not noticed any problems in performance with exceleration or the plugs getting fowled or burned. I have checked them 3 times now just to be sure and have 3k miles on them.

My daily driving is 150 miles per day (75 to work and 75 home).
I use mid grade unleaded gas.
average speed - 75mph - some stop and go traffic.
Same performance in cold and warm weather.

md86
05-05-2007, 01:48 AM
I have since drilled the silencer in my exhaust and have not noticed any problems in performance with exceleration or the plugs getting fowled or burned. I have checked them 3 times now just to be sure and have 3k miles on them.
Well , for one thing , drilling the silencer would tend to lean it out if anything :dunno: . But yeah , I tried an iridium plug in a "problem" cylinder , and it performed no better than the stock plug .