New coils

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  • EvelKeevil
    XSive
    • Aug 2021
    • 50
    • Keevil, Wiltshire, England

    #1

    New coils

    I want to replace the coils on my '79 SF. I was wondering if it might be possible to simply use coils from a later bike - something like an FZS Fazer. Does anybody have any experience or anything to recommend? It would be helpful to find something that puts out a stronger spark but which doesn't need tricky engineering to fit!
  • DEEBS11
    XS-XJ Guru
    • Feb 2023
    • 1895
    • Connecticut

    #2
    You can do a search for coils. The need to be the correct resistance with or without the ballast resistor.


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    • DEEBS11
      XS-XJ Guru
      • Feb 2023
      • 1895
      • Connecticut

      #3
      Didn't we just go through this with you?

      Comment

      • EvelKeevil
        XSive
        • Aug 2021
        • 50
        • Keevil, Wiltshire, England

        #4
        Originally posted by DEEBS11
        Didn't we just go through this with you?

        https://xs11.club/forum/idle-talk-fo...pgrading-coils
        Yes and no. Lots of very helpful and informative information for which I am grateful. What I'm now asking is whether it's possible to simply fit coils from another bike, plug and play. I also have a 1983 Honda CB1100F and have done this successfully on that bike, using coils from a CBR600. It required fabrication of a mounting bracket but has otherwise bolted on and is producing a far better spark than the original coils.

        Comment

        • DEEBS11
          XS-XJ Guru
          • Feb 2023
          • 1895
          • Connecticut

          #5
          Like I said, you need to use a meter & measure the resistance of the coil primary terminals and tell us what the number is. Should be around 3 ohms.


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          • jetmechmarty
            Master of XSology
            • Nov 2003
            • 8008
            • Coldwater, Mississippi

            #6
            Google's AI says:

            Ignition coils from Honda VF series motorcycles (such as the VF750, VF700, or VF1000) are commonly used as "plug and play" replacements for the Yamaha XS1100, particularly on 1981 models. These are typically 3-ohm coils, making them suitable for the stock ignition system.
            Compatible Honda Coil Options
            • Honda VF Series Coils: These are often cited as a direct fit, allowing users to cut the original Yamaha spark plug leads and solder them to the Honda coils.
            • Aftermarket "Universal" 12V Coils: Many aftermarket 12V dual-wire ignition coils designed for Honda CB/Kawasaki KZ/Suzuki GS models with 3.0 to 3.8-ohm resistance also work.
            • Dynatek DC1-1: While not a Honda coil, these 3-ohm aftermarket coils are highly recommended for the XS1100.
              YouTube +4
            Installation Considerations
            • Resistance: The 1980+ XS1100 models generally use 2.5-ohm or 3-ohm coils.
            • Mounting: While they work electrically, you may need to modify the way the coil is mounted to the bike, as the bolt holes may not match perfectly.
            • Wiring: The yellow (+) wire on the aftermarket coil connects to the Black/White (ignition/kill switch) wire, and the black (-) wire connects to the blue (points/condenser) wire.
            • Ballast Resistor: For early models (1978-1979) that use a ballast resistor, you may need to bypass the resistor if using modern 3-ohm coils.
              YouTube +3
            Always confirm the primary resistance (ohm) of the coils to avoid overtaxing the XS1100’s Transistorized Control Ignition (TCI) unit.
            I bet all this came from this forum>
            Marty (in Mississippi)
            XS1100SG
            XS650SK
            XS650SH
            XS650G
            XS6502F
            XS650E

            Comment

            • DEEBS11
              XS-XJ Guru
              • Feb 2023
              • 1895
              • Connecticut

              #7
              If they turn out to be 3 ohm make sure you bypass the ballast resistor.


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