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Sparkless in St. Pete

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  • Sparkless in St. Pete

    First, let me say that the bike was running in December/January. Not running well, needed a carb cleaning and sync, tanks was bleeding minute rust particles through the inline filters. Carbs were cleaned yesterday and remounted. Tank is now sealed and ready to go back on the bike. I rigged a day tank this morning to facilitate sync and that pert worked out well. I expected it to start right up. It didn't.

    After confirming there was gas getting to the carbs, I pulled a plug (#1) to test for spark. No spark. Then I pulled #2. Also no spark. Since the coils fire 1 &4 and 2&3, and the likelihood of both coils going bad simultaneously was low, I started looking at electrical issues. The fusebox was replaced in December with the one TopCat sells and the bike ran then (and all the lights were brighter!)

    I have two TCI units, both confirmed working back in November (and the one I'm using was working in Dec/Jan). I pulled the red wire/white stripe from the coils at the Y connector-and was getting 10.1 volts. The battery was at 10.1 volts also. It was turning the starter over well enough-but is that enough juice to energize the ignition system?

    I've cleaned the main ground from the battery to the chassis some time ago. The only other ground I can find is from the batter tray to the middle drive? is there another one to look at?

    Can anyone provide a trouble shooting routine to go through?
    1978 XS1100E "in progress"
    St. Petersburg FL

  • #2
    Hey Rlundy,

    Battery voltage is too low. First, you can do a quick test with just some jumpers from a car battery to the bike and see if it will start.

    TCI needs about 10.5 volts for the electronics to work. You either need to recharge the battery, or also later double check your charging circuit to make sure it's working right. But the Reg/Rect and alt doesn't generate much charging current at IDLE, and can actually DRAIN the battery with extended idling.
    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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    • #3
      OK, I put the battery charger back on the battery for 10 minutes (since my first post). Volts are 12.25, even with the charger off the battery. Need to go back and check from the fuse panel up to the Red/White Stripe Y connector that takes volts to the coils. I did look for a spark after the battery volts came up, but saw nothing.

      Could the ballast resistor cause this behavior? Also, I read the tech tip on replacing plug wires, where it tells you what the ohm measurement should be on each coil. But which point do you hook the Multimeter's test leads to? Electrics are a weak subject for me.

      Thanks!
      1978 XS1100E "in progress"
      St. Petersburg FL

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      • #4
        I tested each coil for ohms by placing the multimeter's test probes on the orange wire's connection to the coil and the red/white stripe wire's connection to the coil. Same thing on the other side, except the wires were gray and red/white stripe. Readings were 1.8 on one coil and between 1.8 and 2.1 on the other coil (Meter wouldn't settle down). Is this where I'm supposed to get 1.5 ohms?
        1978 XS1100E "in progress"
        St. Petersburg FL

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        • #5
          To Edit the post just above (I cannot figure out how to edit my posts?) I ran down the street and got a good Fluke Multimeter from a friend. Both coils now show 1.5 ohms across the low tension leads. My old radio shack multimeter was bouncing around and I decided it might be giving me erroneous readings-time for a new one.

          I also retested some voltage measurements. I've got 12.27V at the battery terminals, but 11.65V at the coil+ lead. I have checked, cleaned and dialetric greased every connection I've come across including the ballast resistor (I have not gotten to the connectors behind the new fuse panel). When cranking, the volts seemed to drop to 10.3V. Which is lower than the 10.5V TC says I need. I'm going to check the electrolyte in the battery and charge it over night.

          I did snip a half inch off the #1 and #4 plug leads then screwed the connector back on. Still no spark.

          Qs:

          1. How do you troublshoot the plug connectors? I tried a continuity test, not even sure if that should work or not.

          2. How do I test the plug wires?

          Robert
          1978 XS1100E "in progress"
          St. Petersburg FL

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          • #6
            If you pull the spark plug caps off the wires, they should be about 5K Ohms between the wire side and the plug connection. The coils should measure 15K Ohms between the two spark plug wires.
            The big thing is your battery. The bike WILL NOT FIRE if the voltage drops below 10.5 volts. If it drops below while cranking, NO SPARK, end of story. If the battery is older than two years, and your NOT sure of it, replace it.
            You CAN put a jumper cable from your car to the bike to try and see if the extra amps/volts will fire it. Hook the jumper as follows,
            Black - Negative battery terminal on car to engine mount bolt on bike.
            Red - Positive battery terminal on car to post on battery side of starter relay switch.
            You can jump the bikes in this fasion with no problems, as long as you have Positive to positive and negative to frame/engine ground.
            Ray Matteis
            KE6NHG
            XS1100 E '78 (winter project)
            XS1100 SF Bob Jones worked on it!

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            • #7
              The battery could still be bad if it ts drawing down that much. I had the same trouble with a car battery, and had it load tested, the result showed a bad battery.

              Try what TC originally suggested and jump the battery from a car battery, then disconnect it and see if the charging voltage is correct after starting the bike.

              Also check all your grounds and connectors for corrosion.
              Guy

              '78E

              Quidquid latine dictum sit, altum videtur

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              • #8
                DiverRay and Guy-thanks for the responses. I thought the voltage was dropping too much-and the battery was below the lower line in tow cells. Its only about six months old, but is one of the cheapo autoparts store batteries. I added some distilled water, we'll see if it comes back up. I've kept this on my charger for long periods of time and it looks like it boiled some electrolyte.

                Now I can at least test the spark plug wires and plugs.

                Thanks guys.
                1978 XS1100E "in progress"
                St. Petersburg FL

                Comment


                • #9
                  Sounds like the battery, as others have said, be sure to check the pick up coil wires underneath the timing cover. if the wires break completely, you will get no spark, it can happen to just one or both. it's likely a battery issue, but check the wires fro breakage all the same as they can manifest themselves as all kinds of weird issues. just a thought, have a nice day and ride safe
                  I am the Lorax, I speak for the Trees

                  '80 XS1100 SG (It's Evil, Wicked, Mean & Nasty)

                  '79 XS1100 F R (IL Barrachino)

                  '00 Suzuki Intruder 1400 (La Soccola)

                  '77 KZ400s (La Putana)

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                  • #10
                    Just to be clear..

                    In my former post when I said "disconnect it" I meant disconnect the car battery from the motorcycle battery, not to disconnect the motorcycle battery from the battery leads on the bike.

                    I'm pretty sure you know what I meant...but disconnecting the bike battery while the bike's running will cause the regulator to spike the voltage and may fry your TCI.
                    Last edited by Guy_b_g; 05-25-2009, 02:10 PM.
                    Guy

                    '78E

                    Quidquid latine dictum sit, altum videtur

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                    • #11
                      Understood Guy b g.

                      After some time in my moaning chair, I think some of the drop is coming from the bad connector in the headlight bucket, the one that is tied to the ignition key switch. When I got the bike, it was dead and I finally traced the problem to that connector. The PO told me it "died" when he tried to jump it from a car. The connector is pretty burned, I was able to clean and use some dialectric grease back in October to get the bike started. Since I noted a voltage drop of 12.27V at the battery to about 11.65 at the fuse panel, I'm thinking I need to go ahead and bypass that connector with individual disconnects. I think I've read posts that say a member has access to these connectors? Will have to do a search for the name.

                      I did check the pickup wires, Lorax-mine look beautiful, though I didn't troubleshoot it completely.
                      1978 XS1100E "in progress"
                      St. Petersburg FL

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                      • #12
                        The member that has the electrical connectors is Geezer. I've replaced the connection you are referring to with a heavy duty connector plug from an auto parts store. HTH
                        2H7 (79)
                        3H3

                        "If it ain't broke, modify it"

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