Sparkplug question

Discussion in 'Touring Models' started by baldharleyrider, Sep 6, 2010.

  1. baldharleyrider

    baldharleyrider Member

    85
    16
    0
    Hopefully someone can help. Found an old set of autolite plugs in the garage today still in package. can anyone tell me if I can use them on the 2003 road king. The number on them is 65 and I have seen the number on the ones now are I think a 4165. Didn"t know if they were interchangeable or not
     
  2. dbmg

    dbmg Experienced Member

    5,800
    153
    318
    Best plugs for the bike OE plugs. Using something other than OE may cause more headaches than they are worth.
     
  3. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

    4,633
    83
    101
    Check it out:

    Spark Plugs - Harley Davidson Community

    I personally run Champion plugs in my bikes' engines. Always have.

    TQ
     
  4. nvsteve

    nvsteve Member

    76
    0
    0
    Autolite 4165 is one step hotter than stock. Correct # is 4164. many run one step colder (4163). I've never had an issue with Champion, Autolite or NGK.
     
  5. motorking

    motorking Member

    5
    0
    0
    Good Morning,
    I work at Autolite as the tech manager. The 65's are for an older HD. The correct plug for your bike is the 4164, what you have now is one heat range too hot and I do not recommend using a hotter heat range unless you run in cold climates or experience difficult cold starting. The plug I would recommend is the XS4164. That is a iridium alloy fine wire plug that is the very best spark plug technology available today. If you can pm me your address, I will send you a set to try out. To everyone else reading the thread, I only have one set to give way sorry.
    Let us know what you think after you try them.
     
  6. Hoople

    Hoople Account Removed

    7,198
    0
    34
    MotorKing, while we have you on the line! (your trapped now!:)) Can you tell me a little about the standard HD 6R12 plug. Things like an AutoLite Cross. I believe the 6R12 plug is made by Champion. What is the true Base number for that 6R12 plug (example L87Y, L88A etc). Is the AutoLite cross to the 6R12 plug a resistor plug and if so what is its nominal value in ohms. On the later model bikes, HD uses the Delphi Ion Sensing ignition coil. Will changing the plug, change the operating characteristics of the Ion sensor sub-system?
    I have used Autolite plugs many many times in the past with Great results and it is a Very Fine product.
    Thank you for any insight you can share with us.
     
  7. glider

    glider Veteran Member

    25,464
    108
    44
    Spark Plug X Reference Chart - Harley Davidson Community
     
    1 person likes this.
  8. motorking

    motorking Member

    5
    0
    0
    Hoople,
    Sorry for the long wait to reply. The 6R12 plug crosses to the Champion
    RA8YC, also the 8812 and 9701. The Autolite XS4164 and Copper core 4164 are both resistor plugs. I dont have the resistance value but can measure a few if its important to you. I spoke with our chief engineer this morning and he assured me that our plugs are compatible with all IOn sensing ignition systems. He said most new cars are equipped with some kind of systme like that today and we have to make sure we are compatible to avoid misfires.
     
  9. Hoople

    Hoople Account Removed

    7,198
    0
    34
    Thank you MotorKing. That is Great info I have been looking for. The only reason I asked about the resistance was because when I measured the genuine 6R12 it was off the charts and made no sense to me. In the past most resistor plugs I have measured were in the range of 5K - 10K,, tops and it was more or less the same reading if the plug was hot or cold. I have never seen a plug with more than 10-12K of resistance. But on 4 new 6R12 samples, the resistance was 32K cold and 3K Hot. Just crazy numbers that made no sense...

    Tks again.!
     
  10. motorking

    motorking Member

    5
    0
    0
    Hoople,
    There is a simple reason for what you are seeing. Most all spark plugs fall into the 3-8k ohm resistance range as a rule of thumb. That particular brand uses a coil spring loaded resistor. The coil can corrode and not have a good connection when cold. If you tested the resistance on a HVR tester, (this is a test stand that uses a 5kv current through the plug while measuring resistance) you would not likely see the high resistance, or the plug might flashover if the resistance was high enough.