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  • #1

    Losing spark when hot

    Hey, folks.

    Once the bike gets good and hot, after about 20 minutes or half an hour of riding, I get one coil that cuts out. Generally, it's the 1&4 coil, but at least once, it was the 2&3 coil. I've replaced the coils twice, and installed a relay to provide full voltage to the coils, and I'm still getting this issue. Next step will be to start troubleshooting voltages at the TCI, but I thought I'd post here to find out if anyone's had the same issue.

    Thanks,
    Brian
    '80 SG with motor from a '82 XJ
    Tags: None
  • #2
    The other place to look is the pick-up coils. That area does get the heat of the engine and could be effected by it. If you have not already, you may want to replace the wires to those coils, or at least give them a really good inspection.
    Life is what happens while your planning everything else!

    When your work speaks for itself, don't interrupt.

    81 XS1100 Special - Humpty Dumpty
    80 XS1100 Special - Project Resurrection


    Previously owned
    93 GSX600F
    80 XS1100 Special - Ruby
    81 XS1100 Special
    81 CB750 C
    80 CB750 C
    78 XS750

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    • #3
      I don't think it's the pick up coils. I fixed the pick up coil wires in the spring, and since the problem can switch back and forth between which ignition coil fires, but never happens to both at the same time, I'm pretty sure it's got to be either in the TCI or a problem with power to the TCI.

      Thanks,
      Brian
      '80 SG with motor from a '82 XJ

      Comment

      • #4
        Let me know when you solve this one. I'm still trying to isolate the pickup coil wire break that I've been looking for. Your symptoms are identical to mine. Just haven't found the break yet.
        '81 XS11 LH (MNS)

        "On a scale of 1 to 10, I have an eleven!"

        "Excess is easier to say than XS,"

        Comment

        • #5
          Check the P/U coil plug connection behind the fuse panel, then up to the TCI. The TCI might also have cracked solder joints which can be re-heated. A visual inspection can be done by removing the cover.
          2H7 (79) owned since '89
          3H3 owned since '06

          "If it ain't broke, modify it"

          ☮

          Comment

          • #6
            Whats this relay for the coils you speak of? So you have a 80 XS with a XJ motor and I am assuming you used the XS ignition system or did you go with the XJ ignition system? You also say you have replaced the coils before, what coils did you use, NOS or aftermarket? Are the y 1.5 ohm coils or 3 ohm coils? Do you still have the ballast resistor in there or not? How did you fix the pickup coil wires, did you just put in a small chunk of wire or did you cut the wire off near the coil and then run a new wire all the way to the factory splice down in the wire loom outside the timing cover?

            Sorry for all the questions the relay thing just got me thinking...
            Nathan
            KD9ARL

            μολὼν λαβέ

            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
            SS Brake Lines
            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

            Comment

            • #7
              Originally posted by natemoen View Post
              Whats this relay for the coils you speak of? So you have a 80 XS with a XJ motor and I am assuming you used the XS ignition system or did you go with the XJ ignition system? You also say you have replaced the coils before, what coils did you use, NOS or aftermarket? Are the y 1.5 ohm coils or 3 ohm coils? Do you still have the ballast resistor in there or not? How did you fix the pickup coil wires, did you just put in a small chunk of wire or did you cut the wire off near the coil and then run a new wire all the way to the factory splice down in the wire loom outside the timing cover?

              Sorry for all the questions the relay thing just got me thinking...
              No problem about the questions. The relay is a mod. It switches on with power from the red/white ignition wire, and I ran a new wire from the battery to power the ignition coils. It is an XS ignition system with aftermarket 3 ohm coils. The first pair were the black ones from Mike's XS, and now I've got the green Mike's XS coils. The ballast resistor has been removed. The pick up wire fix was from near the pick up coil to the splice in the loom just outside the timing cover.

              I'm on my way out there now to see what kind of voltage the TCI is getting.

              Thanks,
              Brian
              '80 SG with motor from a '82 XJ

              Comment

              • #8
                Maybe I am having a brain dart or thinking of something else but isn't there only supposed to be 9v going into the coils?
                Nathan
                KD9ARL

                μολὼν λαβέ

                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
                SS Brake Lines
                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

                Comment

                • #9
                  Fixed!

                  Originally posted by natemoen View Post
                  Maybe I am having a brain dart or thinking of something else but isn't there only supposed to be 9v going into the coils?
                  Maybe that's the case if you're using the stock 1.5 ohm coils. I think that's the purpose of the ballast resistor -- to reduce the voltage to the coils. The Green coils from Mike's XS are supposed to be good for full voltage.

                  The problem was my pick up coil wire fix. One of the pick up coils wires was long enough that under the right circumstances, it could contact the spinning plate. The insulation wore off, and then it would ground out, and lose the pick up coil signal. I replaced the faulty wire with a new one. I think I must have been mistaken about the time that I thought the other coil quit.

                  Thanks for the replies!
                  '80 SG with motor from a '82 XJ

                  Comment

                  • #10
                    I understand the ballast resistor and all that but I still think even without the ballast resistor its still not the full 12
                    Nathan
                    KD9ARL

                    μολὼν λαβέ

                    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
                    SS Brake Lines
                    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

                    Comment

                    • #11
                      Hey, Nate.

                      I didn't mean to say that you didn't understand; I'm just curious because I wasn't getting the full 12-14 V at the coils, and now I'm wondering if it was supposed to be like that. I assumed the voltage drop was a bad thing. Maybe I should undo my mod since it wasn't my problem... I doubt it's helping anything, and I've probably just added a possible point of failure by installing that relay.

                      Anyone else have any thoughts on this? I'll be sure to report back if I fry something with this mod.

                      Thanks,
                      Brian
                      '80 SG with motor from a '82 XJ

                      Comment

                      • #12
                        No I was not offended or anything, I am just trying to figure it out now. And no one is choking in with answer, and I think I somehow managed to fry my tci so I can't just go check for myself.
                        Nathan
                        KD9ARL

                        μολὼν λαβέ

                        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
                        SS Brake Lines
                        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

                        Comment

                        • #13
                          I'm running the coil relay mods on both my XS11's and the power difference is very noticeable. No problems so far. The reason for the drop in voltage at the coils is 30 yr. old wiring and the long path the wire has to take thru the ignition switch. I gained almost 2 volts up at the coils with the relay mod. Some people insist the correct way of solving the voltage issue is to go thru the wiring harness and re-do all the wiring and connectors. IMHO, the relay mod does the same thing, even better. If for some reason the relay went bad and left you stranded, just power up the coils with the trigger wire and you're on your way.

                          http://www.xs11.com/forum/showthread...power+ignition
                          2H7 (79) owned since '89
                          3H3 owned since '06

                          "If it ain't broke, modify it"

                          ☮

                          Comment

                          • #14
                            Yeah I just checked mine and I have 11.7 volts up at mine. Don't know what I was thinking about.
                            Nathan
                            KD9ARL

                            μολὼν λαβέ

                            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
                            SS Brake Lines
                            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

                            Comment

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