Iridium plugs in your Airhead?

Discussion in 'Airheads' started by headtube, Nov 25, 2012.

  1. headtube

    headtube 6 mesas de invierno!

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    Anyone using Iridium plugs? I have had great success with Brit bikes using these plugs. Anyone know the Iridium equivalent to the recommended Bosch plug for the 79 R100RS? Thanks.
    #1
  2. craydds

    craydds Long timer

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    #2
  3. RecycledRS

    RecycledRS Along for the ride

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    I have been considering trying the iridium plugs also but they seem to be the resistor type only so it would mean changing the spark plug caps to the no resistance type.
    #3
  4. GypsyWriter

    GypsyWriter Yup, I'm a girl.

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    I always used resistor plugs in my regular (resistor) caps on my GL500 and never had problems. Is there any reason why they wouldn't work in an R100? I'm considering this for my '88 GS.
    #4
  5. mfp4073

    mfp4073 Long timer

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    Can someone post a pic of the difference between resistor wires/non resistor wires and is there a way to ID resistor plugs/non resistor plugs visually?
    #5
  6. batoutoflahonda

    batoutoflahonda Long timer

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    For me any way, not sure if it's worth the money. Between the carbon build up and oil that invariably gets drawn in through the breather in the air box and finds it way to the left plug.....I just run what's cheap and in spec. Clean them and regap with tune up.
    #6
  7. DoktorT

    DoktorT BigBrowedNeandereer

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    How many manufacturers in the world use WIZBANG spark plugs as factory install?? NONE, ZERO, NADA

    Not one of these teams of qualified engineers has found them viable for thousands of motor designs. Any improvements noted are so small as to make them far too expensive in a rational sence. A 2% benefit cannot overcome a doubling or more of the cost.

    If you are not running good enough with stock plugs, the plugs are not the problem and different plugs will not fix you.
    #7
  8. motu

    motu Loose Pre Unit

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    Heaps...that means lots and lots. If you haven't pulled many sparkplugs in your life, then get a sparkplug catalogue from any manufacturer, in the front section there will be photographs - 2,3, and 4 electrodes, extended tips, shielded electrodes, V grooves, taper seats etc. Wizbang everywhere.

    Iridium ? I don't see the point, but try it and see. I'm using Bosch W78 Plus 4's. Doubled my HP and halved the fuel consumption.
    #8
  9. wmax351

    wmax351 Been here awhile

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    For airheads, there isn't a big advantage (or any) for using exotic multi electrode plugs. The combustion chamber is designed for normal plugs. However, the iridium has to do with the electrode. It allows it to be smaller and last longer. In that regard, it shouldn't matter. The plugs will last longer, and spark well longer, but will cost more. So its a matter of choice.
    #9
  10. rambozo

    rambozo Been here awhile

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    my two running airheads have standard Bosch plugs but I tend to use
    fancy plugs on some of my cars and bikes, silver plated in my cb750
    (very short life) and platinum in my gt turbo, can't remember what I have
    in the others

    Anything that helps a bit is good in my book but I doubt I'll bother on the
    airheads
    #10
  11. chasbmw

    chasbmw Long timer

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    Wizbang spark plugs are to give extended service life in todays vehicles, think replacement @ 25-35kmiles rather than the normal 5k miles on our bikes.
    #11
  12. wmax351

    wmax351 Been here awhile

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    Think 100k miles. It's really remarkable.
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  13. digger440

    digger440 Adventurer

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    Exactly, whizzbang plugs are meant for a engine with high efficiency I.E. a very tightly controlled combustion process. These old aircooled tractor motors (while very reliable) have too much variation in combustion chamber temps with minimal fuel control. Modern fuel injection has maps to match the fuel delivery rate precisely to internal temp, atmospheric temp, engine speed and load (and other stuff).

    An old motor with carburetors will not keep the Wizzbang plugs clean enough to take advantage of the extended service intervals and the wizzbangs do very very very little, if nothing at all to promote combustion efficiency. You would not put iridium plugs in a 1972 Ford with a 300 6cyl and expect them to last 80k-90-100k miles even if the motor was fresh.

    On these antique motors save yourself some money, buy a quality "normal" plug and inspect them at the correct intervals.
    #13
  14. DoktorT

    DoktorT BigBrowedNeandereer

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    Anyone who has any experience with aluminum spark plug threads knows that means teardown and thread restoration too many times. But hey, you need a complete valve job by then anyway.
    #14
  15. craydds

    craydds Long timer

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    + 1 . Iridium plugs provide no advantage over standard plugs.
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  16. cycleman2

    cycleman2 Been here awhile

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    I've run Iridium plugs in other motorcycle engines and they do make a difference in driveability. You should be able to find the cross reference you need and they are certainly worth a try. I wouldn't worry too much about adding the 5k plug resistance to the plug wire resistance, with the Iridium's narrower plug tip, they don't take as much voltage to fire.

    I used them in some first generation Goldwing's which had point ignition with no issues. I also currently use them in my Harley and there is a noticeable difference ( to the better ) between them and the stock plugs.

    So go ahead and try them.
    #16
  17. RecycledRS

    RecycledRS Along for the ride

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    +1 for cycleman's explanation and results.

    Others have had similar results even documenting a 2hp gain on Yamaha xs650 and 750s on dynojet testing (see http://www.xs650direct.com/products-27.html site).

    As the xs engine has a similar combustion camber shape as the airhead I thought it would be worth a try. Yes the plug is expensive but if it extends the service life and if it improves the engine performance even marginally it would be worth the extra cost. The reduced voltage required to fire a "pin" type electrode should provide reduced fouling and improved starting (or so the theory goes).

    While cycleman may well be right about not worrying about the plugs built in 5k resistance, I tend to like to duplicate the original ignition specs as closely as possible so as not to stress the coils.

    Just my thoughts and I'm no expert.
    #17
  18. _cy_

    _cy_ Long timer

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    ebay price is $25ea .. ouch... checked Oriellys who had em for $7 ea
    for $15, I'll give em a try ...

    BMW R80GS R80ST R80RT R80 ngk IRIDIUM spark plug 6637
    #18
  19. supershaft

    supershaft because I can

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    Not running 5k resistance caps isn't about the coils. It's about the ICU and hall effect sensor. Running less resistance IS hard on them.

    I run them in my truck but I only change plugs every 100k miles. Other than that I have my doubts about any performance change. I have never noticed any difference running platnum or whatnot. I sure didn't notice any difference with split fires but that fad seem to be over. In my bike? I had just as soon change regular plugs versus cleaning longer lasting ones. The crude WILL build up on them!
    #19
  20. jackd

    jackd Long timer

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    The only time I ever had exposure to Iridium spark plugs was on De Havilland Beavers or high performance Twins back when I started my aviation wrenching career. Performance enhancement? I didn't believe this was the reason that we used them. It was merely to improve serviceability on these engines between scheduled maintenance checks. Standard plugs would erode severely between the 100 hour intervals that existed between plug removal and testing. Many times the rear plugs on the Pratt & Whitney 985's would be seized and removal might mean the damaging of the cylinder head/spark plug holes - best to leave them in and look with a flashlight through the front plug hole and see how they were doing.... Throw some Iridiums in the back plug hole and things held together longer. On the high performance horizontally opposed engine end of things, the bottom plugs would always get covered with all the junk - just the same way our dual plugged Beemers do in their much easier working environment. So all you folks who think that you're creating a race machine by throwing in these plugs, by all means do so. I'll carry on running my NGK's which never seem to erode at all.....
    #20