6R12 HD Plug Color help

Discussion in 'Engine, Fuel and Exhaust' started by Hoople, Jun 27, 2010.

  1. Hoople

    Hoople Account Removed

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    I am running HD 6R12 plugs just like the book calls for. When I pull my plugs they are "egg shell" to white in color. Nothing I do will make my plugs tan in color. I have cross checked my A/F ratio with two different instruments and the engine is not lean by any standard. I just can not figure this out.

    My A/F ratio at idle is in the low 13's. Cruise is mid 13's and WOT is mid 12's. If I had an air leak it would show up on the the Infra-red exhaust analyzer. The bike runs great. I have no concerns at all with it's performance. Starts great, pulls strong to red-line, idle is great.

    As a matter of fact my gas mileage is only in the mid 30's which by itself should make the plugs tan.. but they are near white.(both front & rear)
    What gives? I just can not understand it.

    Does anyone REALLY have tan plugs (front & back) when they check them. Only FI bikes please..
     
  2. Bud White

    Bud White Well-Known Member Retired Moderators

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    todays fuels dont color the plugs like they used to
     
  3. glider

    glider Veteran Member

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    I finally get to help hoop! :D

    You're knocking yourself out for nothing. VERY rarely will you get the nice tan color on the plugs any more without the tetraethyllead of years past. The colors you get now are from the fuel additives and not an indication of the proper A/F ratio any more.

    What we should be concerned about it the coloration of the ground electrode. You should see it change colors just about on the bend to check the proper heat range and that you have no balls of metalic deposit on the insulator that would indicate detonation.

    [​IMG]



    [​IMG]
     
    Last edited: Jun 27, 2010
  4. Hoople

    Hoople Account Removed

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    Really!.. I had no idea. As a matter of fact I am using Amoco most of the time.

    I even went so far as setting my idle A/F fuel ratio to where the engine was almost choking with fuel and I could not get the porcelain color to change to a tan color.

    I could not figure it out and it really had me concerned... Tks!!
     
  5. glider

    glider Veteran Member

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    There ya go then :D
     
  6. Hoople

    Hoople Account Removed

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    Glider, So I go out to the garage and pull the plugs. And as expected, the ground electrodes are Black.

    I wondered where all this Gas was going. I was pouring it in there and the porcelain color would just not change. But the Ground electrode sure was. I had not even consider it.

    So as James Brown would say... "I Feel Good!"...:p

    Tks!
     
  7. glider

    glider Veteran Member

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    Any time Hoop!

    You'll see a ring of carbon on the shell and the first thread or two which is pretty much normal but not on the ground electrode.
     
  8. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    I had heard this before about unleaded gas. Thank you for the pictures, and yes now I know for sure my fueling is a bit rich, but just fine based on the picture.

    [​IMG]