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998 Spark Plugs

Discussion in '748 / 916 / 996 / 998' started by Aboringname, Mar 30, 2017.

  1. Hi,

    It's time for me to change spark plugs and I'm looking for some advice please ....

    I have a standard '02 998 for simple road use. I have full Termi's and run a PC3 that has been mapped for my bike.

    What do you recommend please in terms of:
    - Standard or Iridium.
    - Make.
    - Model Number.
    - Gap setting.

    Any pitfalls to look out for please ?

    Many thanks.
     
  2. See pic . Explanation given in album under user albums. Spark plug body length can cause an issue unless you have a thin walled plug socket. Just my experience but if it saves you dime pain....

    20150830_204057000_iOS.jpg
     
  3. I use Iridium plugs in my 998 set to a large gap, about 0.030"\0.032". I have never had a problem using this type of plug although some may disagree.

    The large spark plug gap is to allow a fatter\stronger spark, according to theory.

    I use NGK plugs and machined down a conventional socket on a lathe to allow for the need to use a thin walled socket.
     
  4. Thank you for your helpful answers.
     
  5. Evening. Just going through the service items I can do on my own on my 998.
    Took the old spark plugs out (champion RG4HC) and replaced them with champion RG4HCX.
    The length between both was the same apart from the nut being lower which meant sanding down the plug socket from the tool kit. Gap set to .7 and tightened down but I can’t find out googleing the two what the difference is if any. Anyone fitted these or know what the difference the X is?

    Ian
     
  6. Use to get nearly a 10hp gain on Vtec Honda's with bigger plug gaps ... use to run a rolling road :p
     
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  7. For what it's worth, I did a service on my 998s this year and the original plugs are Champion RG4HC. I bought the listed equivalent NGK CR9EB plugs and they are longer that the Campion plugs so they now sit on my shelf as I'm trying to get some more Champion plugs. I would welcome comments as to other peoples experiences with different makes of plugs.






















    i
     
  8. Bob, I’m wondering if the ones I’ve fitted are the same but updated...
    It’s the first time i’ve changed them in 3 years and they still look in decent condition
     
  9. I am not a fan of iridium plugs nor Champions, had misfiring at high revs on them (both) from new so do not use them. I always stick with NGK equivalents to the OEM spec. If you don't have access to a lathe then a suitable thin wall socket is widely available on ebay
     
  10. Champion are for your lawnmower, use NGK in your bike...
     
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  11. Perhaps I should have made myself clear. its the threaded part that goes into the head further, ie it sticks into the combustion chamber further than the OE Champions.
     
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