Spark Plug Boot Resistance

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • jeffasaurus2
    • Jan 2026

    #1

    Spark Plug Boot Resistance

    So this might be an easy question, or an unnecessary question, but...

    I ordered some replacement Spark Plug Boots off of Z1 enterprises, they're rated at 5K Ohms. Now on my coils I should be getting 21-25k Ohms restistance for the secondary (Plug to White or Black). With the stock Plug Boots I was right around 22-23k Ohms. With the new ones I'm more like 17-18k Ohms.

    I know that this difference is caused by the boots as the stock ones read right around 9-10k Ohms (disconnected from the wire), as opposed to the 5k Ohms on the new boots.

    Should I be worried about this? I feel like the new boots would be better but not if the resistance is wrong. Is it possible that I simply ordered the wrong resistance boots or are they all the same?

    Any insight is welcomed.
    Thank you.
  • rustybronco
    Forum LongTimer
    Bard Award Winner
    GSResource Superstar
    Past Site Supporter
    • Jul 2005
    • 14961
    • Marysville, Michigan

    #2
    I'm thinking 13~15k plug wire to plug wire less the plug caps measurement is in the ball park.
    Last edited by rustybronco; 01-09-2013, 03:23 PM.
    De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

    http://www.thegsresources.com/_forum...35#post1625535

    Comment

    • jeffasaurus2

      #3
      So I shouldn't worry too much about the caps? I think without the cap I'm right around 12-13k so it'd be the low end of your ballpark but still 'close enough'.

      They certainly seemed to run just fine before I started tinkering with things. I'd imagine that simply replacing the caps shouldn't change too much.

      Comment

      • rustybronco
        Forum LongTimer
        Bard Award Winner
        GSResource Superstar
        Past Site Supporter
        • Jul 2005
        • 14961
        • Marysville, Michigan

        #4
        Factory spec on the spark plug caps is 5K. If you are at 23K total You should be all right. Anything less then that, I'd start worrying about shorted 'turns' on the secondary side of the coils.
        De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

        http://www.thegsresources.com/_forum...35#post1625535

        Comment

        • jeffasaurus2

          #5
          But with the new 5K Caps I'm only coming out to 17-18k.

          With the old caps that read 9-10K I come out to 23k total...

          Comment

          • rustybronco
            Forum LongTimer
            Bard Award Winner
            GSResource Superstar
            Past Site Supporter
            • Jul 2005
            • 14961
            • Marysville, Michigan

            #6
            13~15K+10K= 23~25K

            Double check you readings with a different meter.
            De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

            http://www.thegsresources.com/_forum...35#post1625535

            Comment

            • jeffasaurus2

              #7
              Yeah, and 13~15k + 5k = 18~20k. As is given with the new caps. Which is under the 21~25k within spec.

              I doubt its the meter as the 5k caps read 5k on it.

              Comment

              • rustybronco
                Forum LongTimer
                Bard Award Winner
                GSResource Superstar
                Past Site Supporter
                • Jul 2005
                • 14961
                • Marysville, Michigan

                #8
                Is there only one cap on each coil or two? and bike are you talking about? the one in your signature?

                ***EDIT*** never mind. I just looked at the parts diagram for a GS450TXZ. One plug cap per coil.
                As you were... don't mind the man behind the curtain...
                Last edited by rustybronco; 01-09-2013, 07:33 PM.
                De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

                http://www.thegsresources.com/_forum...35#post1625535

                Comment

                • jeffasaurus2

                  #9
                  Haha, yeah. Probably should've specified.

                  Comment

                  • jeffasaurus2

                    #10
                    Anyone else have any input?

                    Comment

                    • tom203
                      Forum Guru
                      Past Site Supporter
                      • Aug 2010
                      • 8925
                      • Norway,Maine

                      #11
                      Do the new boots work OK? If yes ,I wouldn't worry about the math. the old boots might be giving a false ohm reading
                      1981 gs650L

                      "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

                      Comment

                      Working...