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Coil a #1 and #4 keeps going bad

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  • Coil a #1 and #4 keeps going bad

    Like the title says coil A keeps going bad. I rode the bike for about 15 mins once I first got it running and a coil went bad. I replaced it with a manga coil. All was good. I took the bike out for an hour the other day and the coil went bad again. It reads fine on the post with the connectors. But when checking the secondary it gets nothing. I almost killed the bike leaving a light, and that is when it went bad. It was fine for the whole time until I almost killed it. When I almost killed it the bike nearly turned off but I saved it, and it was bad immediately after that. What could be causing this coil to keep going bad? I am thinking bad regulator possibly? Thanks
    81 H

  • #2
    Are you using 3 ohm coils?
    Nathan
    KD9ARL

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    1978 XS1100E
    K&N Filter
    #45 pilot Jet, #137.5 Main Jet
    OEM Exhaust
    ATK Fork Brace
    LED Dash lights
    Ammeter, Oil Pressure, Oil Temp, and Volt Meters

    Green Monster Coils
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    Vision 550 Auto Tensioner

    In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

    Theodore Roosevelt

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    • #3
      Yes 3 ohm coils
      81 H

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      • #4
        Could be the pick up coils or ignition module. Have you tested them? They could be failing when hot.
        Slow down and enjoy life. If you are in that much of a hurry, you should have left eariler.
        Current rides:
        80 XS1100SG
        82 JX1100
        83 Venture Royale
        86 V-Max

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        • #5
          Are the plugs new and the right type? What kind of plug wires do you have? Do you have resistor ends on the wires for connecting to the plugs, and are they good?

          If the coil secondary is going open, then it's because you don't have the right 'load' on it.
          Fast, Cheap, Reliable... Pick any two

          '78E original owner - resto project
          '78E ???? owner - Modder project FJ forks, 4-piston calipers F/R, 160/80-16 rear tire
          '82 XJ rebuild project
          '80SG restified, red SOLD
          '79F parts...
          '81H more parts...

          Other current bikes:
          '93 XL1200 Anniversary Sportster 85RWHP
          '86 XL883/1200 Chopper
          '82 XL1000 w/1450cc Buell, Baker 6-speed, in-progress project
          Cage: '13 Mustang GT/CS with a few 'custom' touches
          Yep, can't leave nuthin' alone...

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          • #6
            Sounds to me like it wants to be traded to an owner in Oklahoma.
            Greg

            Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid.”

            ― Albert Einstein

            80 SG Ol' Okie;79 engine & carbs w/pods, 45 pilots, 140 mains, Custom Mac 4 into 2 exhaust, ACCT,XS850 final drive,110/90/19 front tire,TKat fork brace, XS750 140 MPH speedometer, Vetter IV fairing, aftermarket hard bags and trunk, LG high back seat, XJ rear shocks.

            The list changes.

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            • #7
              I used the oem caps on the wires. I have also switched the connectors the coil so that coil A would fire from the coil b connector and tested for spark and still no spark on coil pack 8. Also the magna coils have the removable wires so I removed the wires and tested directly where the plug connects to and there is no reading. Also I used one oem wire that I cut and trimmed and one new copper core wire. Also the plugs are brand new the correct kind. I have swapped everything from side to side and still no spark on coil A so I believe it is breaking internally.

              Greg, if no one buys this thing within the next couple weeks I have some pretty gnarly plans for it.
              81 H

              Comment


              • #8
                Originally posted by crazy steve View Post
                Are the plugs new and the right type? What kind of plug wires do you have? Do you have resistor ends on the wires for connecting to the plugs, and are they good?

                If the coil secondary is going open, then it's because you don't have the right 'load' on it.
                Hey Steve,

                He didn't capitalize it, but he said it was a Magna Coil....so I'm assuming he means a coil from a Honda Magna?? I remember you talking about some of the newer types of coils that require Dwell control otherwise they burn up when used in OLDER types of ignition systems. Is the Magna coil that type??

                IF not, then aside from the TCI or Pickup coils not triggering it, he says it has an internal OPEN on the secondaries...? SO....low voltage to it wouldn't burn it up would it...would just cause a weak or no spark???

                T.C.
                T. C. Gresham
                81SH "Godzilla" . . .1179cc super-rat.
                79SF "The Teacher" . . .basket case!
                History shows again and again,
                How nature points out the folly of men!

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                • #9
                  Originally posted by Chicagoxs View Post
                  Greg, if no one buys this thing within the next couple weeks I have some pretty gnarly plans for it.
                  You hate me don't you?
                  Greg

                  Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid.”

                  ― Albert Einstein

                  80 SG Ol' Okie;79 engine & carbs w/pods, 45 pilots, 140 mains, Custom Mac 4 into 2 exhaust, ACCT,XS850 final drive,110/90/19 front tire,TKat fork brace, XS750 140 MPH speedometer, Vetter IV fairing, aftermarket hard bags and trunk, LG high back seat, XJ rear shocks.

                  The list changes.

                  Comment


                  • #10
                    Originally posted by TopCatGr58 View Post
                    Hey Steve,

                    He didn't capitalize it, but he said it was a Magna Coil....so I'm assuming he means a coil from a Honda Magna?? I remember you talking about some of the newer types of coils that require Dwell control otherwise they burn up when used in OLDER types of ignition systems. Is the Magna coil that type??

                    IF not, then aside from the TCI or Pickup coils not triggering it, he says it has an internal OPEN on the secondaries...? SO....low voltage to it wouldn't burn it up would it...would just cause a weak or no spark???

                    T.C.
                    The 'dwell control' coils will burn up on the primary side if used on a non-dwell control ignition. He says he's taking out the secondary side, so that usually points at a plug/plug wire issue. If the coil is trying to fire into a too-high or open circuit, this causes voltage to go up and you can get insulation breakdown inside the coil. This causes internal arcing, and either a short (too-low ohm reading across the secondary) or it burns it open, usually the latter. This could even be caused by a high-ohm connection between the spark plug body and the cylinder head; paint, corrosion, or non-conducting anti-seize. This is why the FSM says to never check for spark by lifting a plug wire and seeing if it arcs to ground without the plug attached.
                    Fast, Cheap, Reliable... Pick any two

                    '78E original owner - resto project
                    '78E ???? owner - Modder project FJ forks, 4-piston calipers F/R, 160/80-16 rear tire
                    '82 XJ rebuild project
                    '80SG restified, red SOLD
                    '79F parts...
                    '81H more parts...

                    Other current bikes:
                    '93 XL1200 Anniversary Sportster 85RWHP
                    '86 XL883/1200 Chopper
                    '82 XL1000 w/1450cc Buell, Baker 6-speed, in-progress project
                    Cage: '13 Mustang GT/CS with a few 'custom' touches
                    Yep, can't leave nuthin' alone...

                    Comment


                    • #11
                      Originally posted by crazy steve View Post
                      The 'dwell control' coils will burn up on the primary side if used on a non-dwell control ignition. He says he's taking out the secondary side, so that usually points at a plug/plug wire issue. If the coil is trying to fire into a too-high or open circuit, this causes voltage to go up and you can get insulation breakdown inside the coil. This causes internal arcing, and either a short (too-low ohm reading across the secondary) or it burns it open, usually the latter. This could even be caused by a high-ohm connection between the spark plug body and the cylinder head; paint, corrosion, or non-conducting anti-seize. This is why the FSM says to never check for spark by lifting a plug wire and seeing if it arcs to ground without the plug attached.
                      I always check for spark with the plug in the cap. Hm I will have to keep looking.
                      81 H

                      Comment


                      • #12
                        I should also mention the bike ran perfectly for about an entire of riding so it was definitely at full running temp. It didn't mess up until I almost killed it. I suspect something with the voltage dropping way down and then spiking back up when I saved it messed it up.
                        81 H

                        Comment


                        • #13
                          You mentioned a Magna coil failing, but what kind of coil was the first one that failed?
                          I think I have a loose screw behind the handlebars.

                          '79 XS11 Standard, Jardine 4/1, Dyna DC1-1 Coils, 145 mains, 45 pilots, plastic floats - 25.7mm, XV920 fuel valves, inline fuel filters, speed bleeders, Mikes XS pods, spade-type fuse block, fork brace, progressive fork springs/shocks, manual petcocks, 750 FD, Venture cam chain tensioner, SS brake lines

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                          • #14
                            It was an oem coil
                            81 H

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                            • #15
                              Did you replace both coils with Magna coils or just the one that went out?
                              I think I have a loose screw behind the handlebars.

                              '79 XS11 Standard, Jardine 4/1, Dyna DC1-1 Coils, 145 mains, 45 pilots, plastic floats - 25.7mm, XV920 fuel valves, inline fuel filters, speed bleeders, Mikes XS pods, spade-type fuse block, fork brace, progressive fork springs/shocks, manual petcocks, 750 FD, Venture cam chain tensioner, SS brake lines

                              Comment

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