Iridium Plugs

[pooh]

I have put a pair of NGK Iridium plugs in my M900ie they appeared OK at first but after a short period of running they appear to be playing up. When I take the plug out and turn the engine over with the plug touching earth it appears not to spark but if I pull the plug away from the earth I get a spark to earth from the plug. Any ideas folks?

Ian :grump:

[Rally]

Are you sure its not just you see it when it has to jump the gap but not when it is close? The spark is a double one I believe and doesn't show that well normally anyway.

[analogue_rogue]

are they both doing it because that sounds like the ceramic insulator is breaking down....

[pooh]

the spark from both of them aint very good but the front one is non existant and I have swapped front to back and no difference also swapped the coils over and no difference. Running out of ideas, I thought these iridium plugs were the mutts but not sure now. unless anybody has a better idea other than the plugs which have only done a maximum of 20 miles running.

Pooh

[analogue_rogue]

can you run the bike with one of the plugs out and look at the running spark? check its regular in central, when the regulator breaks down a tell tale is when the spark is not nice and stable. which would also cause your sparking issues...
whats the bike running like?

[pooh]

Bike not running well had it on the dyno yesterday and had to stop the mapping cos kept dropping onto one cylinder then back to two. Mixture going crazy as well right one minute then rich as hell due to no spark. Getting feed to coil and injector so thought it was the coil but as said tried different coil with no difference so everything is pointing to the plugs but they are new.

Pooh

[gary tompkins]

Maybe worth trying another set Ian and getting a refund on the duff plugs?

[Stafford]

I had a set of iridium plugs in the 900ss, just the same as you they seemed to fail straight away and appear to have no spark. Not sure what the deal is with these plugs as they seem a bit marmite to me. Back on analoge plugs as it were and all is well. I have a set for the S2R yet to fit, will advise.

[Hubcaps]

Even though NGKs are great in my car (Subaru Legacy) I don't rate them on my S4R. Mine was running on 2, then one, then 2 etc and generally pretty **** really, until I changed to Desmo IXU 27s. They cured the rough running instantly! Give them a try.

[chris yeatman]

have had a lot of ngk plugs going down, being in the car trade as well, we use a lot of them.
i had a set in my old m750 that done the same thing as urs, tbh i dont know wots in my s4r that was tuned up by dave wood racing.

[CK & AK]

Ian - as you know, we've run the Iridium in ours for the past 9 years - every bike we have and have had in the past have run on these - from the 583 to the 1098s - and AK's 900ie has been running on a pair for 20,000 miles so far..... (cos he is a tight ar5e & wont change them)
AK suggests you may have a faulty one (as GT says)

CK

[jerry]

I have had sets of iridium plugs in my S4 and M750 for 5 years with NO prblems at all...remeber they gap differently from regular plugs

[uksurfer]

Not sure what the deal is with these plugs as they seem a bit marmite to me. Back on analoge plugs as it were and all is well.

same as mate

[Dukedesmo]

I've used iridium plugs in the 916 for the last couple of years and they work fine but when I change them at the yearly service they (and particularly the one from the rear cylinder) are more consumed than normal plugs ever were.

Now this could be because changing to iridium plugs coincided with some engine tuning I had done? but I thought iridiums were supposed to last longer?...

[Dookbob]

I have bought a lot of different plugs over the years of all kinds, and found it not unusual to get quite a few duff ones. When I take them back to where I had them from and ask them to change them , they never bat an eyelid, as if to say that they are not surprised.

[slipperyweeguy]

I note nobody has quoted the part numbers of the plugs they are using or have used. Might be helpful. DCPR8EIX will soak heat differently to DCR8EIX, even though they are the same heat range.
Here is a useful link http://www.ngksparkplugs.com/tech_support/spark_plugs/index.asp?mode=nml

I use DCR9EIX in an S4 and it is sweet, now.
I sold large quantities of NGK plugs (for motorcycles) in my last job, and never had a faulty one.
Some engines just seem to be hard on plugs. The only one I have ever had that ate plugs was one of the original Audi quattros - 5 platinum plugs every 2000 miles. I tried every make and grade of plug available, and settled with NGK.
Your experience may vary.

[analogue_rogue]

like i said originally.. sounds lik ethe ceramic insulater is breaking down .. but it must be a huge coincidence that both plugs have broke at the same time.. try a new set and keep us updated?

[gary tompkins]

.. and AK's 900ie has been running on a pair for 20,000 miles so far..... (cos he is a tight ar5e & wont change them)

CK

Same here CK. Got a set in the solo which have done over 10K, and the set in the trike is now 5 years old and done 24,000 miles. I'm sure it seems to run/start better on them too. Been cleaned a few times but they still look almost new to me - so good value for money IMO.

[pooh]

Well folks been and picked up a standard set of plugs, fitted them and guess what, the bike sounds perfect. It ticks over lovely and picks up great so in my opinion stick with what ducati fit and you wont go far wrong. Other than the cost of the plugs it cost me an hours dyno time not being able to find out what was wrong and also a couple of hours of my time beliving it was something other than the plugs. Bugger!!

Ian

[Dookbob]

Another thing that I found out the hard way is that if you use resister plugs with resister plug leads the motor wont like it. One or the other is best.