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    Firing before the cylinder

    Messed with bike today, put stock pilot jets back in, was dumb to put anything higher than stock when I just had an exhaust on. Anyways the bike was going really well, smooth, quiet idle. The throttle response wasnt that great but it did not have a hanging rev issue, eventually it just shut off and I thought maybe fuel was choking it and that's also why the throttle response wasnt so well.

    I turned the idle screws out about a quarter turn from it originally being 2 turns out and didnt really change anything, had a bit of black smoke but was gone soon after. I put a bolt in the vacuum line at the carbs because I was gonna run it out of fuel before putting back in for the night so I didnt have possible gas sitting in my cylinders, and at one point the bolt shot out.

    Heres the thing, I've had this inconsistent skip, and today it was gone, returned at one point but maybe once or twice, and left. I turned the screws out and it did it a tiny bit but now I'm thinking maybe it's because the bike is firing before it should.

    Reasons why thered be a backfire before the cylinder?


    I know I'm close, I'll link a video of today, this was before the idle screw turns and it just suddenly dying. But it gives hope that its gonna be done.

    https://youtu.be/SnyaHIO1tpE watch the video you'll understand it is close to done.
    Ian

    1982 GS650GLZ
    1982 XS650

    #2
    valves and or timing...
    -Mark
    Boston, MA
    Suck Squeeze Bang Blow..
    sigpic
    1980 GS850G with 79 carbs.....

    Comment


      #3
      Originally posted by mvalenti View Post
      valves and or timing...
      Okay,I didnt know if running lean could be it. Both timing and valves are up to date, I'll see if the timing could need any adjustment
      Ian

      1982 GS650GLZ
      1982 XS650

      Comment


        #4
        Watching your video, it sounds to me that the engines is mis-firing on one cylinder. Which one?

        Start engine and let it idle.... Then remove a spark plug wire. The engine RPM should go down if that cylinder is operating correctly.

        If the RPM stays the same, that is the mis-firing cylinder..

        Comment


          #5
          Originally posted by melchiro View Post
          Watching your video, it sounds to me that the engines is mis-firing on one cylinder. Which one?

          Start engine and let it idle.... Then remove a spark plug wire. The engine RPM should go down if that cylinder is operating correctly.

          If the RPM stays the same, that is the mis-firing cylinder..
          I will as soon as I get some pieces shipped in. I like to believe I'm running on all 4 as of very recent. No gap in the idle, all 4 headers get hot. I have fuel air and spark but I'll checkover the carbs since they're already out.

          I'll do that test forsure though, I've done it before and had a nice buzz go through my hand but it was because plug caps were worn completely.
          Ian

          1982 GS650GLZ
          1982 XS650

          Comment


            #6
            Originally posted by mvalenti View Post
            valves and or timing...
            Not if it's inconsistent.

            Comment


              #7
              The bike sounds alright. Gotta get on and butt (poor mans) dyno it to really know if the fueling and everything else is where it should be.

              Comment


                #8
                It seemed to pull fine and smooth I never gave it a hard throttle but I'd go through most of the powerband just making sure it would hold up to it. I guess I'll give it a real go and see how it acts. I dont think I'm missing kn anything and after watching a bunch if videos of gs650s idling I can say mine is one of the better ones. They never have a complete drone it seems but very close to it, always have a bit of a tick inbetween the idle. Maybe I'm wrong, but I'll be doing a steam test and riding it to see how it goes. Honestly when I rode it the other day I was very pleased with the results other than the idle climb but it wasnt nearly as high as it was and the sound was tons more bearable.
                Ian

                1982 GS650GLZ
                1982 XS650

                Comment


                  #9
                  Originally posted by timebombprod View Post
                  Messed with bike today, put stock pilot jets back in, was dumb to put anything higher than stock when I just had an exhaust on. Anyways the bike was going really well, smooth, quiet idle. The throttle response wasnt that great but it did not have a hanging rev issue, eventually it just shut off and I thought maybe fuel was choking it and that's also why the throttle response wasnt so well.

                  I turned the idle screws out about a quarter turn from it originally being 2 turns out and didnt really change anything, had a bit of black smoke but was gone soon after. I put a bolt in the vacuum line at the carbs because I was gonna run it out of fuel before putting back in for the night so I didnt have possible gas sitting in my cylinders, and at one point the bolt shot out.

                  Heres the thing, I've had this inconsistent skip, and today it was gone, returned at one point but maybe once or twice, and left. I turned the screws out and it did it a tiny bit but now I'm thinking maybe it's because the bike is firing before it should.

                  Reasons why thered be a backfire before the cylinder?


                  I know I'm close, I'll link a video of today, this was before the idle screw turns and it just suddenly dying. But it gives hope that its gonna be done.

                  https://youtu.be/SnyaHIO1tpE watch the video you'll understand it is close to done.

                  Your bike has an electronic ignition. It is not adjustable. Back firing is usually due to excessively rich mixture. That would not be a pilot jet problem. It's a too large a main jet problem, or possibly clip position on the needle.
                  All the robots copy robots.

                  Komorebi-The light filtering through the trees.

                  You are free to choose, but you are not free from the consequences of your choices.

                  Comment


                    #10
                    Originally posted by timebombprod View Post
                    Messed with bike today, put stock pilot jets back in, was dumb to put anything higher than stock when I just had an exhaust on. Anyways the bike was going really well, smooth, quiet idle. The throttle response wasnt that great but it did not have a hanging rev issue, eventually it just shut off and I thought maybe fuel was choking it and that's also why the throttle response wasnt so well.

                    I turned the idle screws out about a quarter turn from it originally being 2 turns out and didnt really change anything, had a bit of black smoke but was gone soon after. I put a bolt in the vacuum line at the carbs because I was gonna run it out of fuel before putting back in for the night so I didnt have possible gas sitting in my cylinders, and at one point the bolt shot out.

                    Heres the thing, I've had this inconsistent skip, and today it was gone, returned at one point but maybe once or twice, and left. I turned the screws out and it did it a tiny bit but now I'm thinking maybe it's because the bike is firing before it should.

                    Reasons why thered be a backfire before the cylinder?


                    I know I'm close, I'll link a video of today, this was before the idle screw turns and it just suddenly dying. But it gives hope that its gonna be done.

                    https://youtu.be/SnyaHIO1tpE watch the video you'll understand it is close to done.

                    Your bike has an electronic ignition. It is not adjustable. Back firing is usually due to excessively rich mixture. That would not be a pilot jet problem. It's a too large a main jet problem, or possibly clip position on the needle.

                    Also sounds like your carb synch is not right either.
                    All the robots copy robots.

                    Komorebi-The light filtering through the trees.

                    You are free to choose, but you are not free from the consequences of your choices.

                    Comment


                      #11
                      I have the dyna on but no it's a short circuit that I've been having, I thought it was firing right next to the carb but I was wrong.

                      My mains are upsized but my problem was during idle speed to about 3500, I think it's fixed but ill find out today if my bike reacts any certain way.

                      The short circuit hides somewhere along my charging system I believe it has to do with my regulator, with the charging system disconnected I have no short circuit or nothing weird happening, I tested my stator but i still need to do the grounds test, but the first test showed fine, my battery is obviously fine, so it leads me to the regulator. If the regulator isnt throwing the short and the stator passes both tests then it would have to possibly do with the red wire that goes from the regulator to the fusebox.

                      Didnt want to start the other day it was so bad, next day with chrging system off it came right up no problem and stayed idling
                      Ian

                      1982 GS650GLZ
                      1982 XS650

                      Comment

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