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‘78 Special - timing issue?

Discussion in 'The Garage' started by Duck749, Oct 13, 2021.

  1. Duck749

    Duck749 XS650 Enthusiast

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    So I was able to replace cam seals which meant pulling advance and point assembly off. Marked timing and reassembled. When going to start bike and check for leaks it just cranks with occasional “gun shot” and flame out one exhaust and no start or running.

    The advance was all keyed which makes me believe this is just a timing issue. Is there a specific advance setup and assume I should just do normal timing verification correct?
     
  2. Jan_P

    Jan_P XS650 Guru Top Contributor

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    It was a log time since I had points
    I would check that the advance unit is operating properly pulling back to retarded position
    then I would check the points installation gapping and check that no short circuit and then timing.
    Shooting in exhaust is to late ignition usually
     
  3. Duck749

    Duck749 XS650 Enthusiast

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    So I did confirm tonight that advance is off, will this alone cause similar issue?

     
  4. Jan_P

    Jan_P XS650 Guru Top Contributor

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    Not entirely sure of the English ...Off meaning not used or Off not at the right position
    But it has to be right fex full retard at startup
    That is something to work on and get right. It means the ignition coming out of sync with valves and pistons
     
    Jim likes this.
  5. Jim

    Jim Beyond the edge is the unknown. Here be Dragons XS650.com Supporter Top Contributor

    Yes, not starting and pops out the exhaust are classic symptoms of being 180° out on timing. Just to confirm it, swap the plug leads and see if it'll start.
     
    Jan_P and Oldfartaussie like this.
  6. Duck749

    Duck749 XS650 Enthusiast

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    Thanks for help and info, moved advance to correct 180deg position, reset timing and one kick fired up and idled good again!
     
    Jim and Jan_P like this.

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