ngk iridium's

Discussion in 'Electrical' started by adrian101, May 9, 2011.

  1. adrian101

    adrian101 Member

    I have the stranded spark plug that came with the engine still, When i get my bike back on the road i want to pick up a new spark plug.. I've read a few topics on here about what spark plugs people use. Lot of people mention the NGK iridium plug as one of the best spark plugs...

    I've been told by a lot of people that the iridium plugs burn/spark to hot for the stranded china two stroke engine, "will destroy the piston". Is this true or BS?

    If it isn't true then what NGK iridium plug do you use because i want one.. lol:D:D:D

  2. SdCruizer

    SdCruizer Member

    all I can say is I use iridium in all my scooters
    but I happened to get a normal plug today and found mine needed to be gapped to 50, like the stock china plug to run correctly

    now if I dropped the cash on an iridium and tried to open the gap that large who knows if I could do it cleanly without chipping it or something
    I wanst expecting to gap it at all
  3. HeadSmess

    HeadSmess Well-Known Member

    iridium is a platinide, much like rhodium and , wow! platinum!

    this means it has a melting temperature well in excess of 1500 degrees celcius.

    its hard too boot. makes nice jewellery and laboratory equipment :)

    they use it in specific style spark plugs for a reason. length of service intervals.

    they dont wear out (as fast as standard plugs)

    youll find them in the REAR CYLINDER BANK ONLY on a car such as a mitsubishi magna V6. why? cause they designed the silly thing so you have to remove the entire inlet manifold to change the plugs! this becomes a major service, and as such, is around about the 150,000 to 250,000 km mark. the front row of cylinders,on the other hand, are easily reached, so use standard plugs.

    a standard plug should be changed every 10,000 or so.

    so what does this mean?

    well, considering platinum sells for twice the price of gold, and that iridium is even more expensive, the plugs are very expensive.

    they make absolutely no difference to spark temperatures.


    this is a function of coil strength, not plug type. more current/voltage makes a hotter spark. not an expensive spark plug.

    combustion temperature is a combination of compression ratio, fuel type, and fuel mixture. the spark has no bearing on combustion temperatures.

    other than to get it to burn in the first place. that bit helps.

    the average lifetime of a HT seems to be less than the average lifetime of a standard plug....

    so why spend all your dollars on a silly plug?

    oh yeah. iridium is hard to re-gap. you arent meant to.

    (yeah yeah, they arent that expensive but you get the idea now, i hope...)
  4. toojung2die

    toojung2die Member

    I have lots of miles logged on my 2009 BikeBerry 66cc and I'm still using the original plug. I haven't even looked at it for over a year. There's a spare plug of the same type in my carry along tool bag. I'm waiting for the expected plug failure I've been warned about. Personally I don't think it's worth the money to put any kind of special plug in these cheap little motors. They're low compression and rich on oil. Plugs are not going to wear out often.
    davidtuerk likes this.
  5. Waxxumus

    Waxxumus Member

    But they last 120,000 Miles.
    I could take this one out and put in 5 other china bikes XD
  6. jaguar

    jaguar Well-Known Member

    I will only use Iridium, it's that good. Not hard to gap either.
  7. ChoppaStile

    ChoppaStile New Member

    I'm a big fan of NGK Iridium, I'll put them in anything. It's good to have 2 or 3 different ones for the seasons, but I found myself cleaning them much more often than other plugs. Such is the price of performance.
  8. Waxxumus

    Waxxumus Member

    How do you go about gapping them jaguar?

    Needle nose plyers, the little hole in the top of the gapping ring?
  9. jaguar

    jaguar Well-Known Member

    yes, needle-nosed pliars or a jewelers screwdriver to pry the ground electrode outward.
    And i just tap it on a hard surface to close the gap any.
  10. HeadSmess

    HeadSmess Well-Known Member

    exactly what the manuals tell you not to do (to any plug) but also guilty.... :goofy:

    but, as for this one...

    if you are cleaning the plug...then its too cold a heat, go down a number or two.... :detective:

    or someone hasnt jetted for "performance"....:devilish:
  11. KCvale

    KCvale Motorized Bicycle Vendor

    I run NGK Iridium's in everything too.
    They are a touch longer so you get a slight compression gain.

    The less expensive BP7HS plug is longer as well and works about as well, I just find the pre-gapped Iridium to never be the problem if it won't start and worth the extra $5.

    If you have a high compression head the plug tip will hit the piston.
    Generally it just flattens the anode but it could damage the head, but no, it's not a Plutonium plug that could go into meltdown and destroy your engine along with a city block ;-}

    The 2-stroke NGK 5944 (BPR?HIX) plug runs your engine as hot as the number choice you put in for ?.
    The higher the number, typically 7 or 8, the cooler the engine runs.

    The trick is you need the engine to run just hot enough to burn everything so the plug doesn't foul.
    General rule is 7 if it's hot where you live, 6 if it's not too bad.

    Note the 4-stroke one for the HS 49cc is NGK 7544 (CR?HIX).
    Last edited: Jun 25, 2015
  12. KCvale

    KCvale Motorized Bicycle Vendor

    I get repairs for 'loss of performance' in like that.

    20 minute job on a good engine...
    We pop the head and check things, clean it up, torque it back on proper and put in an NGK plug for $50 and the story is the same...
    'WOW! This runs better than it ever has!'.

    I've said it for years.
    The single best 'bang for the buck' performance enhancement for the little engines we use is the NGK plug.
    I suspect if you try one 2Young you'll say the same ;-}