Plugs - NGK or Iridium?

[Hedgehog]

Planning on changing the plugs on my 97 standard and wondering what you folks think is the best? I've seen NGK's in sets offered and guess these must be OE (?)... but is there any benefit to be gained from using anything more exotic like Iridium? ???

Cheers

Hope you guys and girls are having a nice Easter break..

[98valk]

search is your friend, don't be afraid. 

been addressed many times with members riding results 

[Chrisj CMA]

Planning on changing the plugs on my 97 standard and wondering what you folks think is the best? I've seen NGK's in sets offered and guess these must be OE (?)... but is there any benefit to be gained from using anything more exotic like Iridium? ???

Cheers

Hope you guys and girls are having a nice Easter break..

Don't waste your money.......stick with NGK stock numbers change them every 50-60K miles and dont even think about them.  But, dont buy them from the bike shop.....get them at your car parts store.....same exact part for a quarter of the price.  Use some anti-seize and dont overtighten and you will never have a problem

[Hedgehog]

Thanks. Naturally I did check 'Search' first (its my friend!! - Ahhhhh!), but just wanted the most up to date / new opinions.

I'm still inclined to go for the Iridium's (can't help but spoil the beast) - it would be interesting to hear from anyone who has fitted these while - by way of a long term test as it were...


Cheers

HH

[Grandpot]

I have fouled a couple of regular plugs.  Changed to iridiums, no more problems.  They are expensive, but I like them.  Each to his own.

[Robert]

I like the Iridium's and if doing a tune up it will be the preferenced plug. NGK makes a good plug but the Nippondenso are also good in fact may be a bit better but I'm not sure that they make these for the Valk. As for NGK Iridium plugs my experience has been they last longer start better and idle smoother. I have put them in cars and seen the results 60k later and didn't need to replace them at that time. To let you know how much I like them I put them in my lawnmower also. I was interested to see if it would make a difference and it does start easier and run smoother. Briggs and Stratton make a Iridium plug that they say is just for that purpose to make the engines easier to start. If you are looking for a big difference there wont really be any.
   Just as a side note the design of the center electrode is such that it doesn't allow it to foul like other plugs that is the reason that some have found these work better. They are also a broader heat range which allows for better performance along with the fact that it takes less juice to fire them. In cars if you have a weak coil I have seen these stay running when other plugs will miss and the coils would fail. I have high voltage aftermarket coils on my bike and have increased the gap to 40k to give a little better spark. That about covers it except for I think they are worth the difference in price.
  Bosch has come out with a new iridium spark plugs and I got a free set from the local rep. I dont like Bosch plugs and was wary about giving them a try even free but my truck needed plugs so I put them in. I can say that I am plesently surprised they are really a good plug. In some applications I dont know why but the Iridium has a very slight miss on occasion not in our Valks it seems more like trucks so I knew that this would put these to test and I tell you the truck does feel better and no occasional miss. I think I will try to score a set of these for my Valk when I have to replace the NGK plugs that are in there now. Bosch has allot riding on this as their plugs were garbage for the most part and the 4 prong deal that they came up with was the worst.

[Chrisj CMA]

If the Iridiums had a different design from the OE like a center fired plug Id get it just for that......I wouldnt need to index them, but since they are the standard configuration I see no advantage for me.........after 60K miles the OE ones look like new, I have never had one foul........Different strokes I guess

[Robert]

Chris there is no standard plug that I would not replace after 60k miles. The porcelain may look good but the edges of the center electrode are worn not a crisp edge and the ground electrode is more than likely also worn to a larger gap than specs. This is why manufactures have gone to platinum or Iridium and some to double platinum because of wear in the maintenance services. I know they probably work ok but I just will not go that long with standard plugs. Just another point to think about indexing is not quite as important with a Iridium plug. Yes you still have the ground electrode possibly blocking the spark but since the spark has such a small surface to jump from there is not the usual spark starting almost from any point around the tip of the plug. So the spark kernel is consistent and ignites more of the fuel consistently and evenly. This is one reason these plugs start better and maintain consistency throughout there life.

[Hedgehog]

As usual, a lot of wisdom on here ... many thanks.

HH.

Iridium's  it is.

[Chrisj CMA]

Chris there is no standard plug that I would not replace after 60k miles. The porcelain may look good but the edges of the center electrode are worn not a crisp edge and the ground electrode is more than likely also worn to a larger gap than specs. This is why manufactures have gone to platinum or Iridium and some to double platinum because of wear in the maintenance services. I know they probably work ok but I just will not go that long with standard plugs. Just another point to think about indexing is not quite as important with a Iridium plug. Yes you still have the ground electrode possibly blocking the spark but since the spark has such a small surface to jump from there is not the usual spark starting almost from any point around the tip of the plug. So the spark kernel is consistent and ignites more of the fuel consistently and evenly. This is one reason these plugs start better and maintain consistency throughout there life.

I agree about the changing them somewhere from 50-60K miles but still after 60K they really look good and I cant tell a difference in performance once the new ones go in.  My bike starts really easy and idles like glass........if these flat six engines are mechanically right, no vacuum leaks, gummed up carbs or valves out of whack, they start easy and run smooth no matter what you run.  Again to each his own, but $12 for all 6 or near that for one depending on which you choose........Ill save the extra dough for higher gas prices

[98valk]

from an early post of mine. http://www.valkyrieforum.com/bbs/index.php/topic,8041.0.html

any stock plug, put the gap at .030, cut back the side electrode so that only half of the center electrode is exposed. round the edges.
I like using the auto lite 4164 which has a necked down center electrode and then mod the side electrode.

http://www.autolitecatalog.com/RelatedInfo.aspx?b=A&f=Autolite/ASP2009SparkPlugTypes.pdf
 see #11

http://sparkplugs.com/more_info.asp?AAIA=&pid=8304     autolite 4164

I don't like the stock plug wires, they are solid core with a big resistor in the cap. consider using moroso blue max spiral core wires, which I use or www.magnecor.com, great info where one will see the truth about spark plug wires.
any specilaty plug, platimun,  Iridium, etc., only work because other parts of the ignition system are weak. This is in Dr jacobs OPTIMIZE YOUR IGNITION! book. http://www.cbsperformance.com/Pages/Jacobs.html
 "those exotic metals have very high resistance, hence why the center electrode has to be so small."
hotter coils, better wires are the answer and modified plugs, which I do for all my vehicles. I was using a set of coils from a blackbird, quicker accel, but they would burn out the dyna ignition, so back to stock now. They wouldn't hurt the stock ICMs.  Also measure the ohm resistance btwn plug brands, they are all different.

http://www.musclemustangfastfords.com/tech/0207mmff_tech/index.html    by David Vizard tells why the plug mod works.

[snohunter]

I've worked in parts for thirty years and used every plug known to man ...In a car use whatever is cheapest never seen much difference.... and ya i know someone will say i put in so and so plug and got better mileage.... and they are right it probably did and it probably needed new plugs hence the better mileage.....now when it comes to my toys a.k.a. motorcycle ,snowmobile,boat nothing but NGK. I am currently using NGK Iridiums in the valk because the rep. gave me a set to try are they better? jury is still out on that seems to run good .is it worth the extra 4.00 per plug ? we'll see how long they last . just my .02 worth

[salty1]

I have run std and iridium plugs, can't say one type is better than the other. I change plugs out at 10000-15000 mile intervals and I use nothing but NGK stds. The cost of one set of irdiums equals four sets of stds.