Most of us have heard about NGK IR (Iridium) spark plugs. These are plugs commonly used in the hope of maximizing performance and efficiency, but how much can it really change your machines performance? We take a look at the facts and me being an automobile specialist myself, I reveal all about it.

The Basics: The primary function of the spark plug is to ignite the air/fuel mixture within the combustion chamber at all RPM’s. Spark plugs must provide a path for the flow of electrical energy from the ignition coil to create a spark used to ignite the air-fuel mixture. Sufficient amount of voltage must be supplied by the ignition system in order to create a spark across the spark plug gap. This is called the ‘Electrical Performance’. All the conventional plugs fail to supply proper voltage when its tip gets carbonized or when the resistance of the plug becomes too high. The resistance power basically depends on many factors. Many people install IR without any high performance plug cables, this can create resistance in the wires when it comes to long term use.

Why? IR is basically connected to an ignition coil through a cable. For IR the best cable is high performance cable and so too is the required coil. The ignition voltage in the combustion chamber is nearly about 18000V. These days’ high performance coils can be found on various bikes, For example a Royal Enfield has coil which gives about 24000V, MSD ignition gives about 44000V. That’s a lot of voltage to be dealing with and in order for it to reach the plug without much loss, the need for high performance cables arises.

A spark plug firing end temperature must be kept low enough to prevent pre-ignition, but high enough to prevent fouling. This is called “Thermal Performance”, and is determined by the heat range.

Plug Replacement Time: Unfortunately, there is no fixed answer to this. As spark plugs grow older, they lose their sharp edges as material from the centre and ground electrodes are slowly eroded away. As the gap between these two points grows, the voltage required to bridge the gap increases proportionately. Even the best ignition systems will be strained to supply enough voltage to completely burn the fuel. It is at this point, that the spark plug would need a replacement.

Replacing worn out spark plugs with new ones (with sharp new edges) effectively restores the ignition system’s efficiency. Misfires are reduced, power is restored, economy of operation is enhanced and emissions are reduced.

Cleaning of IR: Yes, you can clean spark plugs. However, it is good to remember that spark plugs are a vital component, so it’s important to make sure you check to see if it’s worth cleaning before you go through the following steps.

  • If the firing end is wet, make sure you clean the spark plug with a quick drying cleaner. (Examples: contact cleaner or brake cleaner).
  • Sand blast the spark plug using low air pressure and use a dry compound.
  • Completely blow all the sand from the spark plug.
  • Using a wire brush clean the threads and re-gap.

NOTE: Insufficient cleaning of the spark plug may lead to spark plug failure in a very short period of time. Clean the spark plug thoroughly to avoid problems later. Remember, if a spark plug is fouling it’s usually a result of engine side factors or incorrect heat range selection.

Performance gain after installing the plug: A common misconception is that changing spark plugs will result in a large power increase. In most cases, removing even seriously worn out spark plugs will only result in tiny power gains, typically about 1-2% of total engine output. This could be even less for computer-controlled vehicles, primarily because most newer vehicles have more powerful ignition systems and the vehicle’s computer can make adjustments so that vehicle operation is not affected by the resistance generated by the spark plug.

Many people think that simply supplying more spark to the firing tip can and will combust more fuel. What they don’t understand is that most new fuel injected vehicles are designed in a way that they can use even the last drop of fuel. So fitting a better spark plug wont be able to make any sort of changes here as the computer already controls the fuel pump and injector along with the sparkplugs.

When a stock or near-stock engine is given a fresh set of spark plugs, peak efficiency is restored. The power gains that come from this restored state of tune are usually minimal. Any company that tells you that their spark plug will provide significant gains in power in a stock or near-stock engine is making blank statements that may not be supportable.

List of Iridium plugs:

  • NGK IR
  • Denso
  • OWS
  • HKS
  • Autolite Plugs
  • Bosch
  • TRD
  • UMI
  • Volkar
  • MOBO
  • RalliArt
  • Brisk

After Looking at these manufacturers of Iridium don’t ask me which one is the best. Because so far I have used an NGK IR plug. One advice I would like to give IR users is to use a cleaning machine for the plug instead of any emery paper or sharp tool. Always try not to damage the tip of the plug.

– Chinmay Dangre

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  1. Yet another nice article from you… You’ve clearly explained the mechanisam of it…. You really have great knowledge about bikes. Great

  2. hello
    plz tell me from where i can get performance cable for yamaha r15 i havebeen using NGK iridium spark plug but i want to have performance cable

  3. Hi
    Can you please tell me whether I can use a NGK Iridium Spark Plug(NGK IHU) OR to use some other latest spark plugs (if any, plz mention) for Honda Unicorn, model – November 2007.

    Thank you

  4. I have bullet electra 4s. Can i use NGK IR. If yes please tell me the product name and number, so that i can buy. I stay in Mumbai. Thanks.

  5. using only NGK IX sparkplug on my r15 increased litle bit of pickup and now bike easily touches 115-118 timing has been improved but searching for power cord to increase some more performance can anyone help me from where i can get it. i live in ludhiana(punjab) plz mail me at

  6. I am Using NGK Iridium Spark Plug in my HONDA Activa New Model 2010. I am getting problems of Missing because i didn’t installed a Performance Cable. If you guys planning to get 1 NGK Iridium or any Iridium Spark Plug. Better get a Performance Cable of MSD atleast for HONDA and for YAMAHA get a Splitfire.

    These 5 Problem i am Facing due to i have only Installed a NGK Iridium Spark Plug CR6HIX without High Performance Cables and for HONDA MSD 8.5mm Spark Plug Cables are Highly Recommended and for YAMAHA only Splitfire.

    1) Missing Problem – It tends to get Switched Off in Lower RPM’s or While Standing when Throttle is Pressed.
    2) Heating Problem
    3) A Slight change in Mileage (With MSD Cables the Fuel Efficiency will improve drastically atleast 10% in my Case 4 to 5 kmpl increase)
    4) Low and Mid Range is not Strong or Powerful. It Tends to Bottleneck while Pick Up from Stand Still
    5) The Pickup is very slow it goes up very slowly upto 60 km/hr. For Example – If on Stock it does 0-60 km/hr in 10 seconds as company claims now it does it in above 10 seconds as i feel.

    I have installed a K&N RC-1060 Conical Air Filter. In this Case i have 2 options to choose from SOUND and POWER. For SOUND i open up the Air Filter Box for POWER i Close it. With only Air Filter it does 0-60 in 7 seconds only on Unleaded Fuel with 97 Octane it does it in under 5 Seconds or something.

    These all are exact prices of the Products in the Market in New Delhi
    A MSD 8.5mm Spark Plug Cables cost Rs.850 approx
    Splitfire Cable cost Rs.350 (Chinese) Branded will cost Rs.750
    ALL Iridium Spark Plugs Cost Rs.550
    K&N RC-1060 Conical Air Filter Cost Rs.1150
    K&N RC-1100 Conical Air Filter Cost Rs.2250

    • Hi John,

      can you please tel l me from where i cn buy split fire cable for rtr 180 ??

      and one more thing i want to ask, right now i m using a Chinese ir plug is ngk ir plug have an edge over it??

    • bro,i lyk speed… i hv kn filters in ma honda dio v2…..i hv heard tht ngk ir spark plug do give power…….so i wanted to know whether installing ngk ir spark plug do work in ma dio……and which cable is suitable wit ngk spark plug….plz mention the price of it….plz tell me abt it’s lyf tym…..???

    • sir i belive that ur bike hav developed a air bubble in ptrol tank…. which can be treated by decarbonisening the petrol tank from any authorised bajaj service center.

  7. i have a new cbz xtreme(2009) which model of iridium spark plug should i install in my bike can anybody help me…………

  8. to mr kkailas .
    u hv CBZ u can try spark plugs from bocshe these r awesome in performence ……….ok for any assistance reply me okay dude hv fun , ride safe……………………………………..!!!

    NGK plugs are for pulsars and other hard core bikes………….

  9. Hey Bikeadvise mod’s……this article is nothing but an exact reproduction of NGK’s FAQ section. And whats worse in the author claims himself to be an automotive specialist.

    guys…this is a great website and more than anything an awesome initiative….plz make sure you take a good look at the articles before they are actually posted. It would have been completely acceptable if the author gave a mention of the reference from which he acquired the content, but to say things like “I reveal all about it” is a gaudy plagiarism.

  10. I have a 2005 GSX-R 750 with 7000 miles on it. I just installed NGK Iridium spark plugs and I noticed a big difference immediately. The bike even idles smoother. I had the original plugs in it for 7000 miles and never had any noticeable misfires. If you are going to change your spark plugs, pay the extra couple bucks and get the Iridium plugs- its worth every penny!!!

  11. My passion pro’s stock plug started failing at 15k kms itself. I didn’t know that then. After it started giving hiccups which increased gradually. At 18k there are frequent larger hiccups with complete degradation of pickup and speed. It ruined my other works and i had to spend time in mechanic shed. so now i am going to change the sparks at 10k itself. Its only 120rs and don’t want to take chances standing in middle of nowhere. For power bike go for two electrode sparks. It will drastically increase pickup and top end even in a 100cc bike. If you need one and do no where to go, try Apache’s.

  12. I am using cb unicorn2005 model and i am using NGK irdium plug.But i dont know how to clean manualy,because i donnt have proper technical service center.can u help me

  13. I want to installed MSD spark plug cable to my Honda Unicorn, but the problem is that the code which is connected to HT Unit is molded, it is not coming out of the Unit, so please guide me how to put MSD Spark Plug Cable to the Unit.

  14. for my hero hunk which iridium plug s apt?? My bike tends to get off wen the engine gets heated.. is per4mnce cable an important one along with the ir sprk plgss???

  15. i ve hunk 150cc, i ve tuned my carb which turn my mileage from 40 to 33, but it makes a supper ready pickup with a supper color of spark plug (gray blackish)..

    now, prob is when i use maximum torque then some smoke is blown through silencer.
    plz, reply someone about the condition…

    in addition, i use petrol and recommended engine oil.
    so, plzzzz help me.


  17. cn anyone tell me which spark plug and cables is good for my honda dio v2??? I need……which gives more power!!!!!plz mention the price of it……


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