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    sporadic spark

    I have a 78' GS750 that feels like a 450. I had a timing light hooked up to the spark plug wires while it was idling and I noticed that 2 and 3 had a consistent flash (indicating a spark) but when I hooked up the timing light to 1 and 4 wires there was more of a sporadic flashing, not a consistent strobe. Also to note, the higher i revved the engine (past 2000rpms) the timing light would flash more consistently on 1 and 4. It would almost hang above 1700rpm, then go back down to idle with a sporadic flash again.
    To further proove what was going on, when I pulled the plugs 1 and 4 where darker and sooty more so than 2 and 3.
    Keep in mind I have new dyna coils, electronic ignition, and plug wires.
    Do you think this is a timing issue or a dirty connection?
    any advice would be great

    #2
    Did you take off the points cover and check the timing marks?? Did you recheck all the connections to, be sure they arent loose or corroded? Did you check down the wiring harness a ways back from the plugs to be sure there arent any hairline cracks in that old hard plastic wire covering that would cause a static short to the frame? Notice any arching marks on the bottom of the frame tubes where they clamp in?? that sort of stuff is what you want to be looking for. How about the condensors? What about the resistors in the plug boots? You do know about the resistors, right?
    MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
    1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

    NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


    I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

    Comment


      #3
      Could be a bad condition, or just nothing. I get that ghost signal with my timing light too. Bike runs fine.
      Make sure you have 12 Volts on the coils. Have you done a carb sync

      Comment


        #4
        and adjusted the valves..which should be done before a carb sync..
        MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
        1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

        NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


        I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

        Comment


          #5
          Yeah, its just funny how the signal would change as soon as I switch
          between wires. Also, 1 and 4 are the left coil correct? There might be a problem right there. Resistors in the plug boots?
          Its funny because each spark is good and purple, just possibly not
          firing correctly for some reason. I followed the directions on how to time
          the Dyna S system, I did this statically, while turning the crank and listened to the snap of the spark plug. Does the "F-2" mark line up with the stationary mark for cylnder 3?

          edit: I have adjusted the clearances to spec, and no, I havn't done a good synch. just a bench synch

          Comment


            #6
            Adjust them with a timing light. I found that I had to adjust the right hand module a bit to get the timing dead on after being set statically. Are you using the stock coils and wires?
            Last edited by OldVet66; 01-24-2011, 09:35 PM.
            http://www.thegsresources.com/_forum...ine=1440711157'78 GS1000E, Dyna-S ignition, Dyna Green Coils, K&N pods, Delkevic SS 4-1 exhaust, Dynojet Stage 3 jet kit, Russell SS Brake Lines, Progressive suspension, Compu-Fire series Regulator 55402 and Advmonster cree LED headlight conversion.

            Comment


              #7
              yes ...resistors in the plug boots. If you look in the boot with a flashlight youll see a slot for a screwdriver..Unscrew the plug and theres a spring and resistor in there..if you have resistor caps. Take the resistor out and get some 1/8 inck brass rod and cut pieces as long as the resistors and youll now have a regular plug and not worry about being shut down in BFE from a bad resistor.
              MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
              1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

              NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


              I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

              Comment

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