Iridium Plug my first impressions

[xtremerpr]

Hey scooter fans...

This is actually the first thread I have started new , but I just wanted to comment on my first experience using a NGK Iridium spark plug on my UM Matrix150(upgraded to 155cc). First upon installing and starting up my scoot I had to turn down the idle screw since right off the bat it was idling at 3,000rpm's on the normal ngk plug I had it set around 1,900rpms because of rough idling. well after turning down the idle screw to around 1,900 rpms until it was nice and warmed up i turned down the idle screw till it was idling nicely around 1,500rpms, on the normal plug it would rough idle if set around 1,500rpm's so that alone improved with the Iridium plug. Next I took it for a spin and I have to say that the acceleration is much smooter then before on my first observations. will keep testing out and if anything new happens will let you know.


Danny

[sauceboy01]

very nice, keep us posted.

[scooterollie]

Danny;
The "Iridium" plug is often a "Platinum-Iridium" alloy. Like the "Platinum" plug, Iridium DOES NOT have better spark conduction or heat dissipation abilities than the steel or copper electrode plugs. Actually, they are not as good a conductor of electricity or heat as those other metals. In modern applications where vehicles have high energy ignition systems, the spark is "hot enough" to overcome the higher resistance of these metals. The only reason these plugs are used today is because of their superior resistance to electrode erosion over time and thus are good for extended change intervals. As the gap of a plug increases due to electrode erosion, higher voltage is required to fire the plug, eventually reaching a point where misfires occur. A misfire is bad for air pollution and catalytic convertors. Some modern auto ignition systems are designed to work with resistor plugs. Resistor type plugs will not be found in serious race engines. Check this link for some additional info on electrode metals: www.nology.com/silver.html I don't know that much about the ignition system of our scoots other than they have a CDI module (Capacitive Discharge Ignition). The capacitor stores and amplifies the voltage transmitted to the plug gap, releasing it at just the right time depending on RPMs and allowing for a wider gap and hotter spark delivery at the gap (thus better burning of air-fuel mixture) over non-CDI ignitions.

I give the info above just to shed some light on some of the differences in plugs today. Don't know why you experienced such a dramatic increase in RPMs in your scoot. I am not doubting you, just find it curious. Wonder if your first plug was defective? I replaced the O.E. non-resistor Chinese plug with a non-resistor, non-Platinum/Iridium NGK plug in my 150cc scoot out of concern for the quality of the Chinese plug. No difference in performance. Would be interesting to see what happens with a precious metal electrode plug.
ScooterOllie

[90GTVert]

Being the eternal skeptic, I felt the Iridium plugs were all sales hype, but I did try one. I had to admit that it did smooth out the idle, and the RPM's did increase slightly (not as much as mentioned above though). The price of the plugs is high, and maybe they aren't worth it, but I do like them in the one cylinder scooters. I'm not easily impressed, but I do think they are worth using. Stan

[scooterollie]

I had a 1974 GMC front wheel drive motorhome for many years. They used the Olds 455 with the entire FWD drivetrain from the Olds Toronado. In the motorhome, GMC did not go to HEI until '75. Mine had the standard distributor with points and a 40K volt coil. Went through regular plugs every 5K miles. When Bosch brought out the original single electrode platinum plug we tries a set. Every one of us in the club experienced the same improvement - smoother idle, slightly higher RMPs at idle. Plug life dramatically increased.
scootoerollie

[xtremerpr]

scooterollie said:

Wonder if your first plug was defective? I replaced the O.E. non-resistor Chinese plug with a non-resistor, non-Platinum/Iridium NGK plug in my 150cc scoot out of concern for the quality of the Chinese plug. No difference in performance.

I doubt the plug was defective. like you, I also had changed out the stock plug and replaced it with a NGK CR7HSA, changed the plug twice and still had the same rough idling effect. Don't know if it is just the plug or maybe some other settings on the scoot causing it but I know that with the iridium plug it went away for now at least. I read somewhere that with the iridium some gained around 2mph top end...don't know if I gained any top end yet and better fuel efficiency, haven't been riding in a couple a days to test.

By the way the rough idling only occured after I had the 155cc kit installed. it was fine when first installed though. maybe fuel/air mixture screw when I had the NGK CR7HSA plug installed that caused the rough idling???

[Jacine]

From what I hear, the Iridium plug generally improves smoothness, but does not necessarily increase mph. However they tend to last 50000 miles or better and rarely need changing. Never gap them according to the manufacturer. They do improve performance (not speed) in the Yamaha V*

[xtremerpr]

Yeah I don't expect it to increase mph, basically got it for smooter performance and hopefully a little better fuel economy.

[michaelc]

Speaking of Iridium plugs . . .

I just got off the phone with one of the local O'Reilly Auto Parts stores here in Wichita and low and behold, THEY CARRY THE PLUG! I will have one tomorrow morning for the low, low price of just $6.99. You will need to provide the following stock number when you call:

Spark Plug Part No. Stock No. Plug Gap
Iridium CR7HIX 7544 0.028

www.ngksparkplugs.com/apps/motorcycles/make4.asp?id=2628&type=ir

If you don't have an O'Reilly's near by, give your local parts store a call, you never know!!

[fulltiltone]

Most people see an immediate difference when they change plugs. This is in part due to the fact the plugs are brand new and don't have any deposits on them to bleed energy. If you were to run this Iridium plug for 500miles and compare it to a reg NGK with 500miles in it, you wouldn't see that much difference. That said I have an iridium in my scoot and I saw a dramatic difference in idle smoothness when I changed it.

[surfbum96818]

michaelc Great tip I am going to call around to see if I can get them localy also. Funny the major motorcyle shops here in town don't stock the irridium.

[michaelc]

bum,

Actually, it was one of the local shops that told me they get their Iridium plugs from OReilly!!

I picked it up yesterday, didn't see a lot of difference though.

[xtremerpr]

michaelc said:

low price of just $6.99.

Wish they were $6.99 here...cost me $10.00 grrrr

[happyman]

tried to get a plug like that for my scooter they don't carry them... have another question though..How do you start another new post here?? thanks

[surfbum96818]

Happy just go to the Lobby of which ever subject you want to post in ( this 125 and Bigger ) in the lobby look at the top left hand side of the page ( not up at the banner but top of threads box you will see MARK AS READ, NEW THREAD, & NEW POLL just click new thread.
Might I suggest you try the New Poll some time it is a great feature! ALSO check some of the older postings before starting a new thread you may find one simular to what you wanna ask and you can post on it and it will be brought back to the top of the postings list so everyone will kknow it has been updated.

[scooterollie]

Advance Auto Parts can order the plug, just did for me today at $7.38. Will be in tomorrow. I am curious to see what happens. Don't really expect much difference idle RPM-wise but curious about idle smoothness.
ScooterOllie