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  • Mad Mosquito Stutter

    Today I took my first small road trip to my home town of Purcell about 30 miles away. As I was rolling into town after having been cruising at 55-65mph, the motor started to stutter and cut-out. It felt like an ignition problem because it was very uniform. I reached down and fiddled with the spark plug wires which seemed to help a little. I then switched to reserve fuel and after a few seconds it cleared up. I felt dumb because it always catches me off guard when the fuel runs out....

    Here's the bad thing: I filled the tank in Purcell and switched the petcocks back to the 'on' position. Took the scenic route home and as I was pulling into my neighborhood it started cutting out again. I looked at my trip set and I had only been 45 miles since I filled up. I pulled over and switched to reserve and after a minute it cleared up and ran fine.

    I drove it home and looked in the tank and it is nowhere near empty because I can still see gas at the top. Are my coils going bad? What should I check first?
    1979 XS11 Special (slightly modified)
    dubbed the "Mad Mosquito"

    MikesXs Pod Filters
    MikesXs 35k Coils
    8mm plug wires
    42.5 Pilots 142.5 Mains
    (Carb tune by GNEPIG Performance)
    Kerker 4-into-1
    Shaved emblems
    Progressive frt springs lowered 1.5"
    Progressive 11.5" rear shocks
    Harley Dyna rear fender chopped
    Custm side mt tag (apparently illegal)
    Custom Dual Headlights
    Lots of time and hard work.

  • #2
    Fuel lines

    Sounds like a kinked or plugged fuel line , i bet it will run on reserve till the tanks empty.
    Mitch
    Doug Mitchell
    82 XJ1100 sold
    2006 Suzuki C90 SE 1500 CC Cruiser sold
    2007 Stratoliner 1900 sold
    1999 Honda Valkyrie interstate
    47 years riding and still learning, does that make me a slow learner?

    Comment


    • #3
      Hi D-B,

      If switching to reserve fixes it, it is a fuel problem! Do you still have the octy?..... if so, throw it away!

      Disconnect the lines from the carbs, switch on, and see what comes out in the various lever positions.......; does it flow better on reserve than "on"? I would guess that you have paint debris in the in-tank filters, but it could just be a petcock issue, or even the breather in the cap.

      If it runs OK on reserve, it is a MINOR problem; you will get it fixed!

      AlanB
      If it ain't broke, modify it!

      Comment


      • #4
        Try switching to Prime when the problem shows up again.

        Comment


        • #5
          If it turns out not to be a fuel problem

          Pick up coil wires can make it seem to be running outa gas.
          Work intermitently, stop working and then go good for days or weeks.

          My 80G would be just putting along and then start to crap out, few seconds later run just fine. Third time it happened (about 6 weeks after the first) decided to fix em.


          mro

          Comment


          • #6
            The Octy went bye bye long ago. I also have the Prime outlets capped off at the petcocks. I ran the fuel lines according to a diagram from this site including inline filters. The thing is, it ran fine for 45 miles in the "on" position. I will pull the tank and check the flow when I get a chance. When I put it back together it flowed the same in both positions.
            1979 XS11 Special (slightly modified)
            dubbed the "Mad Mosquito"

            MikesXs Pod Filters
            MikesXs 35k Coils
            8mm plug wires
            42.5 Pilots 142.5 Mains
            (Carb tune by GNEPIG Performance)
            Kerker 4-into-1
            Shaved emblems
            Progressive frt springs lowered 1.5"
            Progressive 11.5" rear shocks
            Harley Dyna rear fender chopped
            Custm side mt tag (apparently illegal)
            Custom Dual Headlights
            Lots of time and hard work.

            Comment


            • #7
              Did you check your gas cap vent? IT's a small pinhole and can clog with gas varnish causing vacuum lock in the tank preventing fuel flow?? You can take the gas cap apart to find the little washer/vent piece and ensure that it's little hole is open! JAT!
              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!

              Comment


              • #8
                Fuel Cap Vent

                I knew I was forgetting something! Everytime I park it after a ride I can hear the gas cap hissing. Sometimes I'll come back out an hour later and it's still making noise. I knew it was a vent so I just figured the noise was normal. I'll bet that's the problem. How do I clean it?
                1979 XS11 Special (slightly modified)
                dubbed the "Mad Mosquito"

                MikesXs Pod Filters
                MikesXs 35k Coils
                8mm plug wires
                42.5 Pilots 142.5 Mains
                (Carb tune by GNEPIG Performance)
                Kerker 4-into-1
                Shaved emblems
                Progressive frt springs lowered 1.5"
                Progressive 11.5" rear shocks
                Harley Dyna rear fender chopped
                Custm side mt tag (apparently illegal)
                Custom Dual Headlights
                Lots of time and hard work.

                Comment


                • #9
                  carb clean

                  disassemble all the cap parts and thoroughly clean everything with carb cleaner, you'll see where the vent holes go from the back side to the front. Also would be a good idea to get a new rubber gasket (AA has them) in case yours is dry rotted and spills gas onto that new pretty paint
                  MDRNF
                  79F.....Not Stock
                  80G......Not Stock Either....In the works

                  Comment


                  • #10
                    Thanks!

                    Also, I'm tired....does AA = Ace?
                    1979 XS11 Special (slightly modified)
                    dubbed the "Mad Mosquito"

                    MikesXs Pod Filters
                    MikesXs 35k Coils
                    8mm plug wires
                    42.5 Pilots 142.5 Mains
                    (Carb tune by GNEPIG Performance)
                    Kerker 4-into-1
                    Shaved emblems
                    Progressive frt springs lowered 1.5"
                    Progressive 11.5" rear shocks
                    Harley Dyna rear fender chopped
                    Custm side mt tag (apparently illegal)
                    Custom Dual Headlights
                    Lots of time and hard work.

                    Comment


                    • #11
                      AA

                      A&A Cycle on 15th
                      MDRNF
                      79F.....Not Stock
                      80G......Not Stock Either....In the works

                      Comment

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