Spark Plug Gap

Discussion in 'General Harley Davidson Topic' started by Yetiatlarge, Sep 12, 2008.

  1. Yetiatlarge

    Yetiatlarge Member

    Just came across this forum when I was searching for info.
    I am in some others but I like that this is all Harley.
    I need help with plug gap issue.

    I have a 1970 Electra Glide all stock, "I think" but with electronic ignition.
    Setting for points ignition is .028-.033.
    Should I open them up a bit with electronic?
    I get some pinging when I crack the throttle and plugs are always black when I look at them.
    I have a new Bendix carb this year which helped a lot.
    Any thoughts on this would be appreciated.
  2. Dr. Dolittle

    Dr. Dolittle Experienced Member Contributor Retired Moderators

    I have no expertise in this area (actually not many areas) but there are a lot of REALLY smart folks on this forum that will be able to answer your question.

  3. SledDog

    SledDog Senior Member Staff Member Moderator

    If your plugs are black, you need a carb adjustment/jets. I have no experience with bendix carbs, sorry.

    The increasing/decreasing the gap with not help with this problem....
  4. glider

    glider Veteran Member

    I would say that your ping is more due to the timing rather than point setting, however changing the point gap also changes timing.

    I set the points with a dwell meter and 1/2 the figure on the 4 cylinder scale and set them to 32*
  5. Flashback

    Flashback Active Member

    do what Glider said first. If you still have a ping it could be related to the bike being a 1970 model. If it's not stock and running high compression pistons there will most likely be your problem since decent high octane fuel available at that time isn't now unless you have access to av gas at a rediculous price. Anything over 10.0 or 10.5 to 1 is gonna need 100+ octane to slow down the detonation and run trouble free.
  6. Yetiatlarge

    Yetiatlarge Member

    You might be right about the compression being high.
    It takes quite an effort for the starter to turn it over and she runs great now that I put a new Bendix carb on.
    I got some real bad gas on a trip a few weeks ago and it caused a few problems.
    Drained it out and cleaned carb bowl and now is a little better.
    I am going to increase gap to .035 and give that a try.
    I think I will do compression test and find out for sure.
    I never thought of that.
    Thanks for the interest.
  7. Yetiatlarge

    Yetiatlarge Member

    I have the manual.
    It says up to .033.
    I will try .035
  8. dangerdan

    dangerdan Junior Member

  9. Yetiatlarge

    Yetiatlarge Member

    Just an update on the plug gap problem.
    It was not plugs or carb giving me the problem.
    Turns out my reg was burning out.
    Now have to change reg and stator.
    Need new battery too.
    My riding season is officially over for this year.
    Going to ride the '92 next year while I take the '70 apart for a refit.
    New top end, cam, trans work and electrics.
    She will be in space dock for about a year.
    At least I won't be bored this winter.