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Chasing a short circuit

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    Chasing a short circuit

    Been talking to a guy the past day or two and hes been helping with the charging system getting sorted out. I told him how I have an arc that sounds like a pop but electrical and when it happens that's when my lights flicker. I changed my ground locations to an assured spot to prevent or fix any issues it could cause.

    He said that is a short circuit that I'm having and said it could be anywhere, said have fun looking for hours lol.

    This is what I'll say about the short circuit, sometimes its really bad, sometimes it barely happens, I've even had it dissapear briefly and it was the newest thing my.bike did. When the short happens I hear the pop, my lights dim with the pop, and my rpm goes down about 100ish. Goes back up and lights brighten when the pip clears. Any places to look?

    New ignition system new charging system, headlight loop has been deleted, everything operates as it should but my horn isnt hooked up, doesnt work when i press the button and it used to. Its hooked up how it was when it worked but theres free wires hanging. Alot of connections have been cleaned, the main plugs that run on the frame under the tank, the fusebox plugs aswell as the box itself, ignition (one that uses key) killswitch assembly. Really havent cleaned any in the headlamp but they look good to me.


    I'd like to get the horn assembly hooked up right first I think it's a possible culprit.

    If.i follow the wiring diagram when I turn my key on the horn will stay on, so something's not right.
    Ian

    1982 GS650GLZ
    1982 XS650

    #2
    This pop, does it only happen with the bike running?
    A momentary drop in system voltage with the bike running could be enough to flicker lights and miss a few ignition sparks resulting in exhaust popping.
    The fact that both lights and ignition are affected would suggest a prime suspect being be the main supply wire from the battery to main fuse to ignition switch.
    If it happens running the more likely places might be forward of the tee in to the main supply from the R/R.
    The main harness bundle is subject to a lot of stress at the steering stem and often wires break at this point. You could fire up and provoke the harness at that point by turning the steering from lock to lock or just plain pulling at the harness bundle.
    A more systematic approach it to start stepping out from the battery positive probing for voltage before and after each connector and switch using your third arm to wiggle things.
    97 R1100R
    Previous
    80 GS850G, 79 Z400B, 85 R100RT, 80 Z650D, 76 CB200

    Comment


      #3
      Short circuits will typically blow fuses and/or melt and char wires. If you don't have any such evidence then you probably don't have a short in the wiring harness.

      How are your spark plug wires? Are they original/old? If so when you hear arcing take a look at the wires and see if they are arcing outside the wire. Doing this in the dark helps with seeing any arcing. You can also mist/spray water on the plug wires to provoke a bad wire that is arcing outside of the wire.

      As Brendan said, a drop in voltage can cause a misfire which could be heard as popping. Also a misfire can drop rpms, which will drop charging voltage, which will cause lights to dim during the misfire.

      Comment


        #4
        Originally posted by Brendan W View Post
        This pop, does it only happen with the bike running?
        A momentary drop in system voltage with the bike running could be enough to flicker lights and miss a few ignition sparks resulting in exhaust popping.
        The fact that both lights and ignition are affected would suggest a prime suspect being be the main supply wire from the battery to main fuse to ignition switch.
        If it happens running the more likely places might be forward of the tee in to the main supply from the R/R.
        The main harness bundle is subject to a lot of stress at the steering stem and often wires break at this point. You could fire up and provoke the harness at that point by turning the steering from lock to lock or just plain pulling at the harness bundle.
        A more systematic approach it to start stepping out from the battery positive probing for voltage before and after each connector and switch using your third arm to wiggle things.
        It's not from the exhaust as far as I can tell but I do lose a volt from the killswitch assembly. I did the relay mod but I dojt think that would affect something breaking circuit.


        I will get a video today thankyou for the advice if it stays happening I will start to look for it there, and do as you said.

        I dojt know I'd it helps but when the bike is higher than idle atleast by id say 700ish it wont happen atleast from what I can tell
        Ian

        1982 GS650GLZ
        1982 XS650

        Comment


          #5
          Originally posted by Killer2600 View Post
          Short circuits will typically blow fuses and/or melt and char wires. If you don't have any such evidence then you probably don't have a short in the wiring harness.

          How are your spark plug wires? Are they original/old? If so when you hear arcing take a look at the wires and see if they are arcing outside the wire. Doing this in the dark helps with seeing any arcing. You can also mist/spray water on the plug wires to provoke a bad wire that is arcing outside of the wire.

          As Brendan said, a drop in voltage can cause a misfire which could be heard as popping. Also a misfire can drop rpms, which will drop charging voltage, which will cause lights to dim during the misfire.
          I'd like it to be a misfire but I know how popping from the exhaust sounds my bike likes to do that but it doesnt cause my lights to flicker and rpm to drop, its gotta be some electrical arcing.

          I'll check test the wires forsure but they are new and the plug caps are mostly, everything passes the resistance test.

          Ome thing I did notice is when I was timing my bike with a testlight is get a spark at my coilpack next to where it mounted everytime I let off the advance, now that goes to my spark plugs but the issue I have was happening before I ever noticed this so I dont know if it correlates.
          Ian

          1982 GS650GLZ
          1982 XS650

          Comment


            #6
            Well today was q bust, changed the ground location and I dont think that was the issue because lights turned on and I could spin the motor but the bike didnt want to stay on at all, I could get it to combust but not idle. I checked the spark and all 4 spark consistently. I'm gonna return the regulator and get another. While I do that gonna be messing with the grounds and stuff to get a cleaner setup.

            I tested the stator without the bike running and it showed 1.7ohms from all configurations of using the probe on the stator connections. Now I didnt get to test the stator with the bike running but when the bike was arcing a few days back i checked voltage at battery and it didnt move at all from its voltage when I ran the bike.

            Battery was able to get a charge at oriellys so i dont think it's the battery.


            Why would a regulator fail twice? Is a bad ground the only reason becuaee ifso, they have been changed and I will be making sure everything is cleaner and as stable ss possible while I'm waiting for the new one
            Ian

            1982 GS650GLZ
            1982 XS650

            Comment


              #7
              Did the stator test with the bike running, passes with flying colours. Saw 90acv at one point dont know if that's bad.

              Charging system is completely disconnected from bike and i lost that arc or short circuit. Bike runs on 3 cylinders right now. 4 is the dead one and it's the one with a bit lower compression than the rest. I'm gonna change the leads of 1 and 4 and see if anything changes.
              Ian

              1982 GS650GLZ
              1982 XS650

              Comment


                #8
                So i swapped the leads and nothing happened, I swapped the spark plug with a forsure working one and nothing changed. When I did a compression test cylinder 1-3 have 150psi and 4 has 140psi.

                Where should I start?
                Ian

                1982 GS650GLZ
                1982 XS650

                Comment


                  #9
                  Originally posted by timebombprod View Post
                  Did the stator test with the bike running, passes with flying colours. Saw 90acv at one point dont know if that's bad.

                  Charging system is completely disconnected from bike and i lost that arc or short circuit. Bike runs on 3 cylinders right now. 4 is the dead one and it's the one with a bit lower compression than the rest. I'm gonna change the leads of 1 and 4 and see if anything changes.

                  The stator is three phase. It has 3 AC output wires. If you number those wires, 1,2, and 3, and with engine running, the test is connecting the muitimeter to each of the 3 pairs which are 1-2, 1-3, and 2-3. You will have a voltage reading for each phase test. What are those three readings?

                  Put one probe of the meter on 1 and the other probe of the meter on 2 to check the first pair. Set meter to AC 200v.
                  Last edited by earlfor; 06-04-2021, 03:44 PM.
                  All the robots copy robots.

                  Komorebi-The light filtering through the trees.

                  You are free to choose, but you are not free from the consequences of your choices.

                  Comment


                    #10
                    Originally posted by earlfor View Post
                    The stator is three phase. It has 3 AC output wires. If you number those wires, 1,2, and 3, and with engine running, the test is connecting the muitimeter to each of the 3 pairs which are 1-2, 1-3, and 2-3. You will have a voltage reading for each phase test. What are those three readings?

                    Put one probe of the meter on 1 and the other probe of the meter on 2 to check the first pair. Set meter to AC 200v.
                    I ran that test and at 5k rpm I'm getting 85ACV, I need to do the ground test next.
                    Ian

                    1982 GS650GLZ
                    1982 XS650

                    Comment


                      #11
                      Originally posted by timebombprod View Post
                      I ran that test and at 5k rpm I'm getting 85ACV, I need to do the ground test next.
                      What are the readings on each pair of legs? All three pair must have sufficient voltage. What is it?
                      If the stator leads were going to ground, you would not have any reading.
                      All the robots copy robots.

                      Komorebi-The light filtering through the trees.

                      You are free to choose, but you are not free from the consequences of your choices.

                      Comment


                        #12
                        Originally posted by earlfor View Post
                        What are the readings on each pair of legs? All three pair must have sufficient voltage. What is it?
                        If the stator leads were going to ground, you would not have any reading.
                        While running at 5k at 85acv, if I do a resistance test without it running I get 1.7ohms, I'll have to check the acv while idling. These are doing all configurations that you can with the legs.

                        Ground test is one price on a leg and another on a ground.

                        I'll test it today.
                        Ian

                        1982 GS650GLZ
                        1982 XS650

                        Comment

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