Plug color half and half....

Discussion in 'Sportster Models' started by Lang, Jul 25, 2011.

  1. Lang

    Lang Member

    hi everybody, quick question.... my front spark plug was half too rich and half just getting some color but very little. i never saw a plug that was half and half. i thought maybe manifold leak but i tried all the tests and did not find one. anyone ever seen this? or did i discover something new. thanks
  2. Hoople

    Hoople Account Removed

    I have seen the 1/2 plug coloring also. A big portion of that is caused by the E10 fuels of today. You just can't read plugs anymore like we use too. I have changed the air/fuel ratio by 2 FULL ratio points and saw next to nothing in color change of the plugs.

    I know for a fact my engine is running right on the money but yet the plugs "indicate" my mixture is lean. And believe me it is Not. I no longer see those nice brown/tan plug colors anymore.