BIG deal about Iridium spark plugs?

[rcracer78]

I only have 400 miles on my scoot, but everybody seems to recommend replacing the factory spark plugs. Three questions:

1.What will this benefit?

2.What is the benefit of Iridium spark plugs vs. standard spark plugs?

3.Which one would be a direct replacement of mine?

My manual says DPR7EA(NGK) or DR7TC(TORCH).

[dorian]

Someone else will need to chime in regarding which plug is right for you. But here is what www.spark-plugs.co.uk/pages/technical/iridium_spark_plugs.htm says about Iridium Plugs:

Advantages of Iridium spark plug types
Due to the properties of Iridium, the spark plugs centre electrode can be made with a much smaller diameter than with platinum, Gold or gold palladium and copper/nickel types without sacrificing service life. The spark plugs potential difference is more concentrated at the tiny Iridium tip and hence less 'spark jump' voltage is required - this can be as much as 5,000 volts less than with standard plug types. Ignition is improved and less strain is placed on the ignition system. Benefits of improved ignition/combustion include better fuel economy, increased power/acceleration and especially better throttle response.

[firstscoot]

The Iridium plug did nothing for my scoot. Didn't notice any difference.

[Jacine]

Your plug will most likely be DPR7EIX-9 (NGK) You should have a number after the EA on your plug above. Most likely a 9 for the general environment.

[scooterollie]

Biggest advantage to Platinum and Iridium center electrode plugs is slower electrode wear, thus the plug does not need service (gap adjust) or replacement as often. Because of this, engine stays in tune longer and pollutants are reduced. In the past, many low energy ignition systems using steel electrode plugs needed plug replacement every 6-10K miles. Plugs also fouled out more, broke down more often and contributed to higher pollution. Once you install an Iridium plug in your scoot you can probably pretty much forget about it for the life of your engine - or at least 30K miles.

[bike4miles]

I just stick with NGK myself. They work great and they don't cost a fortune. They come stock on from Honda and other Japanese companies that have a reputation for quality. They make really nice plug wires as well.

[cathouse]

My Roketa Figi 150 came with an NGK plug, I heard so much about the Iridium plug that I went to Advance auto and bought one $.6.50 and while I was there I also bought an auto-Lite $ 1.95 and a Champion $ 1.95 and I can't tell a bit of difference in any of them, maybe the Iraidium plug will last longer but at 4 times the cost I just don't think they are 4 times better.

[pukame2]

My system is stock and changing out the stock plug has my scoot starting faster and idling smoother. As for performance, not too much of a difference but maybe when I change out some jets, weights, or muffler upgrade, I might see a definite improvement.

I got a deal on my iridium plugs at $7; my stock plugs cost $2.95. I'm glad to get a smoother running machine even though it costs a little more. Its a small price to pay when when comparing to hundreds for mufflers, variator kits and such. IMO. the iridium sparkplug is worth spending a few dollars. Your choice...........

Gotta keep moving........

[earlwb]

I have a box of NGK's to use up. So I see no sense in going with irridiums at this time.
Performance-wise, there is maybe (a big maybe) a little bit better RPM if there are less misfires. You might see a slight improvement in miles per gallon fuel consumption, but it is difficult to quantify.
A NGK would typically gain about 100 to 200 RPM over a Torch plug. The Irridium probably another 100 RPM over the NGK. This is due to fewer random misfires where the spark doesn't form up correctly and doesn't fire the fuel in the combustion chamber. Going from the NGK to the Irridium likely won't show any performance improvement that you could feel.

[Aerostudent]

When I went to Iridium NGK, from the random plug that came it the scooter, I saw a very slight improvement in acceleration and responce, as well as a much smoother idle and slightly easier starting (though it wasn't exactly hard to begin with). Worth the money? Depends. I am only running 1 plug, so the extra couple bucks for bragging rights is fine by me. In a car you are looking at 20 bucks or more difference, which wouldn't be worth it unless you are a semi-pro drag-racer or something and need every last 1/100th of an HP our of your engine.

Aero

[phaze]

ngk is the only plug you should be runnin they worked for me 25 years ago when i took my 250r atv for its first ride and has been there since.

[soonerfan]

I switched to Iridium and didn't notice a difference either, I would just stick with what you have if it runs good

[kaintuckdave]

Would the iridium make more difference on a 50cc than on the larger motors?

[slowscootin07]

I think the big picture is being missed here so I'll explain. Iridium plugs may or may not give you a noticeable power increase but what they do is make sure that the power you have isn't compromised by premature wearing out. A regular resistor plug will last no where near as long as as an Iridium one and as said before will most likely last the lifetime of your scooter motor. By having less power requirements needed to fire it, it will also produce far less voltage drop or spikes (those kill scoot coils and c.o.p.--coil on plug types,) and it will also result in a cleaner firing engine.

My manual states to change the plug every 6 months or 3,700 miles(6000 kilometers) so that means 10 plugs in 37,000 miles. An Iridium plug will last you 30K-70K and up on a tuned engine.

For those that don't see coughing up 7.00 for a plug that will most likely last you the lifetime of your scooter is cost effective, then go ahead and spend 2.50 X 10, 15 or more for the same longetivity with regular plugs. I'm a mechanic and it says so on my shirt-

[yarddogbbq]

5834 miles on stock plug. no missing.

but when it needs replaced i probably will do the iridium plug.

yarddog.

[rcracer78]

Thank you ladies and gentleman. This forum is so resourceful. I really appreciate your help.

Now my dilemma is finding this plug. None of my local auto parts stores seem to carry DPR7EIX-9. (confirmed.....thanks Jacine)

Do you have any online retailers that you could recommend?

[scooterollie]

These small scoot engines are also harder on plugs that auto engines. The ignition systems fire the plugs on EVERY revolution, just like a 2 cycle engine, even though the spark is needed only on every other revolution. In addition, these engines spin 2-3X the rpms as compared with an auto engine. All this contributes to faster plug wear and center electrode erosion. As the center electrode wears down, spark weakens, contributing to issues already mentioned. With an Iridium center electrode, erosion occurs at a much lower rate.

[josetann]

Aug 2, 2008 12:19:59 GMT -5 rcracer78 said:

Thank you ladies and gentleman. This forum is so resourceful. I really appreciate your help.

Now my dilemma is finding this plug. None of my local auto parts stores seem to carry DPR7EIX-9. (confirmed.....thanks Jacine)

Do you have any online retailers that you could recommend?

Amazon has it, actually it's from a third-party but you're backed by Amazon if anything goes wrong. It's currently $7.83 plus shipping. Didn't check any other sites, at least you now know of one reputable site that carries it.

[scooterollie]

If you have an Advance Auto store, they have them for $7-8, no S&H.

[csgary]

Iridium plugs will net you a 2 or 3 percent performance gain, which might be nice on a V8, but on a scooter engine, we are talking about a few tenths of a horsepower, so you will definitely not notice it unless you have an overactive imagination. Now it may or may not last 4 times longer than a regular plug, but there is no need to change regular plugs all that often either... Few people seem to realize that you can actually bend the electrode closer when the center has eroded a bit, and it will continue to work just fine. I certainly won't be replacing the perfectly acceptable NGK plug that should last for many thousands of miles on my scoot.

[Karl]

It looks like overall, they're worth the moo-lah.

1) less of a strain on ignition system
2) longer life and don't get out of "spec"
3) lower emissions and better tuned engine

Did I miss anything?

You don't gap these either, do you? Won't that damage the electrode?

Karl

[cathouse]

Advance and O'Reilys auto store has them or can get them overnight, don't know about Autozone, I believe Carquest also can get the overnight.

[cathouse]

I just bought a new Nissan Altima it came with Iridium plugs.

[unaggie]

On the Lance 250's, there was a noticeable increase in idle rpm with the Iridium plug...with no other changes to the engine hardware. The engine has a more defined "thump" sound with the I plug, too. I don't really have any performance observations since we were still breaking in the engines and taking it easy. Starting couldn't be improved at all. I doubt the flywheel makes it past a turn before the engine starts...every time.

Yep, they seem rather costly but I like the results we've seen.

[jagguy]

When it comes to scooters I'm a total newbee but I've been working on engines for over 40 years and I have a view on this. I just changed the plug on my new scoot today. From looking at the threads on the original plug it looks like several of the threads go past the head and into the combustion chamber. There have always been an issue of leaving the sparkplug in an engine with an aluminum head for so long that when it is finally removed after years of service that when the plug is taken out the aluminum threads from the head are fused to the plug and when you tighten the new plug the spark plug hole is stripped.
I haven't seen it written on this forum that "never seize" should always be used on plugs used in aluminum heads like on these scoots.
Also, even though an Iridium plug may last a very long time you should still remove it every year or so just make sure it doesn't get stuck in the head making it impossible to remove without damage.
Hope that made sense.
-g

[Karl]

Aug 3, 2008 18:13:14 GMT -5 jagguy said:

When it comes to scooters I'm a total newbee but I've been working on engines for over 40 years and I have a view on this. I just changed the plug on my new scoot today. From looking at the threads on the original plug it looks like several of the threads go past the head and into the combustion chamber. There have always been an issue of leaving the sparkplug in an engine with an aluminum head for so long that when it is finally removed after years of service that when the plug is taken out the aluminum threads from the head are fused to the plug and when you tighten the new plug the spark plug hole is stripped.
I haven't seen it written on this forum that "never seize" should always be used on plugs used in aluminum heads like on these scoots.
Also, even though an Iridium plug may last a very long time you should still remove it every year or so just make sure it doesn't get stuck in the head making it impossible to remove without damage.
Hope that made sense.
-g

Good point about anti-seize! Bone for you, my friend.

Karl