Iridium plugs in your Airhead?

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

  1. Quedok

    Quedok Been here awhile

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    I have been running NGK iridium plugs in my 1983 R80ST for years now. Haven't touched them except for valve adjustments and they still look great. Much easier to start than before, and they never seem to load up. Best improvement for the money so far.
    #21
  2. headtube

    headtube 6 mesas de invierno!

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    I use Iridium plugs in my 72 Bonneville and also my 70 BSA Royal Star. With non-resister caps. The Bonnie has a Boyer, the BSA, points. For both bikes the recommended plugs are Champion N3 and N4's respectively. I too was skeptical about any performance enhancements, but was told to give it a try by a Brit bike guru. Sure enough, both bikes have seen an improvement in starting, idle and cleaner running with less fouling. They have been problem free. For me, it's worth the few extra bucks.
    #22
  3. jackd

    jackd Long timer

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    I just run NGK BP8ES plugs - I buy them cheap at NAPA using my discount. The plugs I pull out of my GS are clean and un-worn - I change them every year but for no good reason. They could go right back in and perform many years of service ongoing. It idles nicely. It runs well at speed. It always starts but that I put down to the carbs being re-built correctly by myself several years ago.
    #23
  4. pommie john

    pommie john Long timer

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    I tried iridium plugs in my Norton Commando race bike. On the dyno they showed about 1 horsepower improvement throughout the range.
    However.. my drag racing guru friend reckons that if you get a gain from something like different plugs, there's a fair chance that your ignition system is the real problem. You might have a coil on the way out or other HT problem.
    #24
  5. cycleman2

    cycleman2 Been here awhile

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    If you do some research on the web on Iridium Spark Plugs you'll find a pretty consistent 1 or 2 hp gain in most applications. My view of why that is happening is that using them has the same effect as advancing the timing slightly, with no knock conditions.

    They do work and are worth a try. Lots of nay sayers but go ahead and try them, you'll be pleasantly surprised.
    #25
  6. supershaft

    supershaft because I can

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    I have heard the same stories with all sorts of new plug designs. Remember tons of people reporting all kinds of advantages running Autolite plugs in oilheads? It just wasn't so. Still isn't!

    Tracking one hp gains is more complicted than swapping plugs for another run. Oil temps and engine temps need to be duplicated not to mention tire temps and traction and that's just the tip of the iceberg. All that takes time and equipment that most for one reason or another don't have. It's hard enough on an engine dyno, let alone wheel dyno's.
    #26
  7. robtg

    robtg Been here awhile

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    How many airhead riders are going to notice an extra 1-2 hp from super-wizbang sparkplugs when they seldom see full throttle or more than 5000rpm on their tachometer?:D
    #27
  8. jackd

    jackd Long timer

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    Well who knows? Maybe that extra 1 - 2 horsepower will make me slide further back on my seat when I open her up...
    #28
  9. robtg

    robtg Been here awhile

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    Only if you are wearing Levi's and you Armoralled your seat.
    #29
  10. jackd

    jackd Long timer

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    Well there's one thing I did learn in this thread and that is I'm running the wrong plugs in my bike. For some reason I bought BP8ES plugs last time out and I should be running BP6ES - slight oversight on my part. Shows you how much I'm paying attention these days. The funny thing is that I swore she runs better than she used to.. Maybe I'm getting an extra couple of horsepower out of these things.
    #30
  11. robtg

    robtg Been here awhile

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    Sometimes new plugs even if not the correct heat range will run better for a while than old crusty plugs.
    #31
  12. chasbmw

    chasbmw Long timer

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    So would Iridum plugs stay clearer longer, if used as the bottom plugs on my dual plugged engines, both do which tend to foul the bottom plugs?
    #32
  13. jackd

    jackd Long timer

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    Yes.
    #33
  14. cycleman2

    cycleman2 Been here awhile

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    I ran the Autolite plugs in my R1100r and they did work better with that engine than the stock plug. It got rid of the surging that the R1100 series was noted for. There are many posts with information on the benefits of this plug in those engines. It never was about hp gains etc, just drive ability issues. I'm not an engineer so I can't explain why or how, but they did affect ( to the better ) the running of the R1100 engine.
    #34
  15. batoutoflahonda

    batoutoflahonda Long timer

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    Yeah, I don't know. I've had/have two R1100S with well over 150k combined on them. I've run about every spark plug that will fit in the hole. Only time they get replaced is when the electrode is gone. And trust me, I've run them to the size of pencil lead. What makes a huge difference on those bikes is taking the time to really tune and synch the throttle bodies. I have never had a surging issue on a stock R1100S which was notorious for surging. I've also tuned it out of RTs and 1150GS by the same methods. None of the 1100/1150's should surge stock. Surging in modern computer controlled bikes is caused by the bike going from rich to lean as the computer tries to maintain a certain fuel map while looking at a lot of variables.

    As for longevity in spark plugs with the FI bikes, the BMW plugs seem to last the longest. I think I just have NGK's in the airhead, but have used champion and autolite, and really, they all last a really long time, carbon and oil fouling aside. We are talking about bikes that are 30 or so years old. They just weren't weren't made to run on today's gas all the time. If you want to see a real improvement right away, go invest in some pure gas, and by some champions.
    #35
  16. _cy_

    _cy_ Long timer

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    not me .. R80 G/S gets run hard all the time ... err most of the time :D
    have not had a chance to pickup a new set of plugs yet. but for $15 what the heck, it's worth a try.

    drag racing at Zombie Apocalypse Training Camp
    [​IMG]
    #36
  17. mysticerror

    mysticerror Adventurer

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    Sorry to bring this up from the dead, but if one where wanting to use the NGK Iridium Sparkplugs (BPR6EIX) in a later model R100 with and electronic ignition, do I need to change the wires to non-resistive wires since the NGK Iridiums are only available in Resistor Based package? If one where to use the OE Spark Plug wires (5K Ohm) with these resistor spark plugs, will there be adverse affects in the ignition?
    #37
  18. 190e

    190e Long timer

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    No, well yes there has to be an effect because you can't bypass ohms law and some voltage would be dropped across the resistors but it would be utterly insignificant with electronic ignition.

    I wouldn't entertain it with points ignition as even if it appears to work you lost a chunk of safety margin in the spark energy. Perversely it's the points ignition that would get most benefit from fancy plugs if it could be done without excessive resistance. For me this earlier comment says it all:

    #38
  19. Stan_R80/7

    Stan_R80/7 Beastly Gnarly

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    Back in the early 1990's I ran Bosch platinum plugs with some special electrode that was supposed to give performance gains. Those were resistor plugs with stock plug wires. No difference could be discerned. Maybe the spark energy was less? I had no way of measuring that energy.

    I typically change my airhead plugs every 10k miles (or so) and don't think iridium plugs will help. However, on my Suzuki DL650 I installed iridium plugs because they will last 30-50k miles, but I don't expect (and haven't noticed) any performance gain. Adding resistor plugs with resistor wires will (theoretically) result in less spark energy - but I doubt you'll notice. Go ahead - blow ~ $12 (?) on a pair and see how they work, no harm will be done.
    #39