1991 FXR loses spark

Discussion in 'Electrical' started by nascar7613, Sep 28, 2016.

  1. nascar7613

    nascar7613 Active Member

    218
    28
    3
    1991 FXR, dynatek s ignition and coil. The bike will run fine then suddenly quit running. The starter will turn the engine and the lights work, but it loses fire to the spark plugs. Then it will start again without doing anything to correct the problem. It might run good for an hour or so then do it again, sometimes it will run for only a few minutes. I put a new coil on it but no change. It doesn't matter if the bike is warm or cold, the problem will appear either way. Guessing the ignition inside the nosecone but not sure.
     
    Jack Klarich likes this.
  2. dbmg

    dbmg Experienced Member

    5,800
    153
    318
    Get a hair dryer and while bike is cold and running heat up ignition module and see what happens. Bet the ignition is dropping out.
     
    Jack Klarich and HDDon like this.
  3. Jack Klarich

    Jack Klarich Expert Member

    18,544
    153
    399
    Only other possible would be 1 a bad coil 2 bad ignition switch JMO
     
  4. nascar7613

    nascar7613 Active Member

    218
    28
    3
    I noticed something when I was checking the bike. When I have the spark plug out and grounded and the wire hooked to it, I turn the key switch on to off, and I get one spark when I turn the key off everytime on either plug wire. Is that normal or an indication of a problem.
     
    Jack Klarich likes this.
  5. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

    3,602
    103
    296
    That does not sound normal to me. When you cut the power you should have no power to the plug.
    I'd be leaning towards a bad ing switch.
     
    Jack Klarich likes this.
  6. dbmg

    dbmg Experienced Member

    5,800
    153
    318
    You should never have spark at plug unless cranking. Possibly your ignition module with key in on position only is reading a crank signal..... Another thought while bike is running wiggle key and see if you can shut bike off like Jeff is suggesting.

    Another option would be to change the main breaker, there was a recall on it. Maybe up one size. I would start here.
     
    Last edited by a moderator: Sep 29, 2016
    Jack Klarich likes this.
  7. tourbox

    tourbox Senior Member

    1,311
    68
    54
    As far as your spark when turning off bike, I seen this before. I attribute it to the ign. module/points being in the fire position. If you turn the motor over slightly it should stop the spark.
    tourbox
     
  8. Breeze3at

    Breeze3at Well-Known Member

    4,645
    83
    124
    I have a '92 Dynaglide with a Dynatek ign. module. I just went out and grounded a plug (both cyl.) and turned ign. on. No spark on either. I tried to bump to TDC, and got no spark when switch turned on/off. I'm not sure if I WAS on TDC. Try bumping your eng. and see if it always does it no matter where the pistons are. If it does it might be the module. Get back to us, I'm curious.
    P.S. mine is set on single fire position.
     
    Jack Klarich likes this.