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Atlas Spark Plug Color

Discussion in 'Other Norton Motorcycles' started by Bodger, Jun 3, 2018.

  1. Bodger

    Bodger VIP MEMBER

    Joined:
    May 9, 2017
    I know this is not very scientific - not a real plug chop - but the attached picture is a NOS Champion N6Y that was on my Atlas for about 40 miles running at speeds up to 65 mph. The gap is .020. According to the technical information on the UK NOC site this is the correct plug for the Atlas, gapped to (continued below the picture) 15280625952761479382098.jpg .025. (I usually run a NGK BP7ES which is a dark malt color). What do you think? Is the Champion too hot?
     
    Last edited: Jun 4, 2018
  2. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    40 miles is nothing really if you are that concerned about it and have ALL the correct jets in, then obtain
    Gunson Colortune 14mm Kit Colortune Spark Plug Carburettor Mixture Tool and tune the pilot jet spot on;)
     
  3. Bodger

    Bodger VIP MEMBER

    Joined:
    May 9, 2017
    As I said my question was not based on a very scientific observation. I am curious though why the NOC would recommend a Champion plug for the Atlas (N6Y) which is 2 heat ranges higher than the plug recommended for the 650SS (N4). The N6Y seems to be a hotter plug than the, also recommended, NGK BP8ES. The original recommended plug for the Atlas was a KLG FE75 which I believe is equivalent to a Champion N4 or N5. Also the NOC recommends a .025 gap which would seem correct for the later coil ignition Atlas only.
     

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