iridium spark plugs

[cals400ex]

i was just curious if anyone has tried the iridium spark plugs in their bikes? i have them in my car. my car did run better but the plugs needed changed. i do know they aren't cheap.

[MX250r]

Well, I know they work real wel in my 250r. But I haven't tried in a four stroke quad.

[Silverfox@C&DRacing]

you are correct they are not cheap I haven't tried them in the 400ex but they come stock in the 450r, I guess it wouldn't hurt to try but they are pricey.

[cals400ex]

yes, i forgot about that. they do come in the 450r stock. i guess i need to trace the number over from the drp9z plug to the iridium version. i will probably try them out. i also have been told the drp9ea will work in a 400ex but i have never tried it.

[zephead400ex]

Hmmm...let us know what you find Cal!

[Toadz400]

I didn't know they had Iridium plugs for the 400ex. I have been running them in my Banshee for over a year and they are still on the same plugs! I will never go to another kind of plug for my Banshee ever again.

[02Yellow400]

how much are they and where can i get one for a 400?

[Toadz400]

I can't remember if they were $6 a piece or $8 a piece for my Banshee. I got mine at a local Farm and Home, so I am assuming check all hardware and automotive stores that have things for small engines.

[cals400ex]

well i don't know for a fact that they make them for a 400ex but i assume they do. we will find out.

[cals400ex]

well it appears they don't make the direct replacement in iridium. the stock plug is drp8z. they dont make this one in iridium. i am wanting the drp9z in iridium though because i run this cooler plug on my built motor. i assume they don't make the drp9z in iridium either.

i have been told we can also run the drp8ea or the cooler version dpr9ea. i will try to get the drp9ea in iridium i guess. we will see what happens

[wilkin250r]

Just be careful gapping them.

[AtvMxRider]

I use the iridium plugs in all our bikes. They are the best plug I have used. They are a little pricey but I get them for free so it doesn't matter:devil:

[cals400ex]

yes, gapping them is a bit tougher. they are so much thinner. when i put them in my car, my dad was like :eek2: those things are thin.

[PunkA$$]

What exactly are the benefits? Do you get better fuel mileage? If so I'll have to get a set for my sled.

[EPDP99]

whats the difference between the drp9z versus the drp9ea?? ya what will switching to these benifit me. i realize better plugs=better fuel burning which=more power, but anything else??

[wilkin250r]

Spark plugs are exposed to heat, fuel, and carbon, and are obviously designed to conduct electricity. As such, they need to be made of an electrically conductive, non-corrosive material.

Along with all the above, Iridium is very hard, which allows for the electrode to be very thin without it breaking, bending, or corroding away.

When something is charged with electricity, the charge will concentrate more in sharp areas, increasing the electric field around sharp corners or points. This means that spark plugs with very small, thin, or fine electrodes will require less voltage to fire. This increases firing efficiency, will ignite leaner fuel/air mixtures, and greatly reduces misfires.

Copper can be made that small, but it is much too soft, and corrodes away much too fast. Platinum is the next best choice, but Iridium is about 8 times harder than platinum. Generally, Iridium plugs will last much longer than a normal copper plug, because the Iridium is much harder and more corrosive resistant.

The problem with gapping them is because the electrode IS so small and so hard. With a normal spark plug, you wedge your gapping tool between the electrode and ground strap, and then pry it open. This won't work with Iridium. If you pry against an Iridium electrode, it is so hard and small it will dig into your gapping tool. (imagine trying to pry open a sewing machine with your thumb by prying on the needle. You won't pry it open, the needle will just stick into your thumb). Now, the electrode is buried inside your gapping tool, if you pull your gapping tool out, it usually breaks the electrode. You have to get a small set of pliers or specialty tool to bend the ground strap, and then check the gap, rather than pry it against the electrode.

[crazyelece]

iridium plugs have more or better spark and are harder to foul out than standard plugs. That is why they are popular with two strokes. I have a friend who uses them in his cannondale because it is very easy to foul the plugs in a dale. I forget exactly where he got them from but it was off the web somewhere. I'd do a search on ebay.

[hondardr4life]

Should I run a cooler plug in my built motor?

[balls2da-wall]

It would be a very smart idea to run a cooler plug in a built motor...VERY SMART:D :p

[hondardr4life]

Like how much cooler, should I just go to a dealer and ask for a step cooler plug? Will it take away some performance?

[balls2da-wall]

shouldnt take away anyperfomance...i have a 440 and I went from a 8 to a 9. I would say one step down should be sufficient.

[hondardr4life]

Ok, thanks.

[DaleJrFan]

i think i am going to check more into these plugs for my truck and quad!

[Toadz400]

I highly recommend Iridium plugs to anyone, they are definately worth the few extra dollars per plug. Like I said before, I've had the same plugs in my Banshee for over a year now and they still are working awesome, and everyone knows Banshee's foul plugs extremely easy. This was also trying to figure out my jetting and I started out 5 sizes too big! So for awhile I was running it extremely rich and it still never fouled out, get these plugs!:D

[MIKE400EX]

There is an iridium plug equivalent to the dpr9ea-9's, the no. is dpr9eix-9. It has a .036" gap which could be changed easily.
My 400 came with the dpr8ea plug from the factory - I thought they all did?

Here's a helpful converter:

http://www.ngkspark.com.au/iridium/iridium.php

[zephead400ex]

Mike, nice find!

[cals400ex]

here is the difference between spark plugs:

http://www.ngksparkplugs.com/techinfo/spark_plugs/partnumberkey.pdf



this is from NGK's website