Announcement

Collapse
No announcement yet.

Back fire during down shifting gears

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Back fire during down shifting gears

    Is it normal to hear my bike back fire during down shifting of gears to decrease speed?
    Its not a single bang but, several pops until I hit the gas or pop it in neutral.

    1980 xs1100 with straight pipes 4 into 2.
    1980 XS1100 SG

    When in doubt, knock 'em out!

    I will not argue with idiots. They will only try to drag me down to their level and beat me with experience.

  • #2
    Typical with open pipes. If it's real bad, richening up the idle mixture screws may help.
    2H7 (79)
    3H3

    "If it ain't broke, modify it"

    Comment


    • #3
      Check for loose and leaking exhaust flanges. Mine was doing just that earlier in the year. Turned out to be loose flanges. I has taken the exhaust off for a repaint and didnt tighten the flanges enough when putting back on.
      1980 SG. (Sold - waiting on replacement)
      2000 XJR1300. The Real modern XS11. Others are just pretenders.

      Woman (well, my wife anyway) are always on Transmit and never Receive.

      "A man should look for what is, and not for what he thinks should be" Albert Einstien.

      Comment


      • #4
        Straight pipes are going to amplify any exhaust abnormality you have. To some extent, you're going to have to live with it. You can minimize the popping by richening the idle as noted previously. A colortune might be in order. I had always used my calibrated ear to set the idle mix, and it worked well. Richen to stumble and then lean to just clean up the idle. By all rights, that should have been a tad on the rich side. To my surprise, a color tune said it was still a touch lean. It actually put the mix just about where the bike seemed to stumble from being rich. However, the idle smoothed out as they were all brought into tune. So, from that, I would say if you think its too rich at idle, it may be perfect.
        Ich habe dich nicht gefragt.

        Comment


        • #5
          Originally posted by Suckerpunch View Post
          Its not a single bang but, several pops until I hit the gas or pop it in neutral.
          I've got a 4-1 Kerker. It does that too, but I love that sound. Sounds like "I'm slowing down, but I'm not happy about it... let's rip!"

          I haven't synched and tuned the carbs yet (still waiting for some carb parts)... maybe it'll go away after that.
          '80 SG with motor from a '82 XJ

          Comment


          • #6
            On Thunderstruck I had stock pipes and air box, but the ends of the stock mufflers had been drilled out. I had stock jetting and my plugs looked great, bike ran great. However, it always popped on decel like that. No matter how I tuned it, it always did it.
            Life is what happens while your planning everything else!

            When your work speaks for itself, don't interrupt.

            81 XS1100 Special - Humpty Dumpty
            80 XS1100 Special - Project Resurrection


            Previously owned
            93 GSX600F
            80 XS1100 Special - Ruby
            81 XS1100 Special
            81 CB750 C
            80 CB750 C
            78 XS750

            Comment


            • #7
              get used to it...mine does it too. after they get old they just like to backfire........just like people
              testing 1-2-3

              1980 1100 mns

              Comment

              Working...
              X