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What fuel/air screw turns out/in should I start with using cheap emgo pods 78' gs750

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    What fuel/air screw turns out/in should I start with using cheap emgo pods 78' gs750

    Hopefully this post title helps others, because I searched more specifically throughout the form for the 78' gs750 which has smaller stock main jets than other bikes of similar engine size and era, which may produce different results. Also has VS carbs (or VM, whatever they're called that aren't CV ). Has cheap emgo pods which I will replace at some point with UNI's.

    Long story short, after tearing the bike apart to diagnose no fire cylinder 2 & 3, I got cylinder 2 to fire after fiddling with air and fuel screws, but now no fire on 1,3,4 (1 and 4 were firing before going through testing things...). Compression good coils good condensers good it's all good, just a ratio thing.

    What I'm looking for now is a starting point / direction for the air and fuel screws. The idle screw is all the way out (not pushing against idle throttle body at all). I know when I reassembled something isn't exactly perfect and that's why 1 and 4 aren't firing anymore, and that's ok. Just want to get it dialed in.

    Thanks!
    -MD
    78' GS750

    #2
    Fuel - 7/8
    Air - 1 1/2
    Also, bench sync them before reinstalling
    1978 GS 1000 (since new)
    1979 GS 1000 (The Fridge, superbike replica project)
    1978 GS 1000 (parts)
    1981 GS 850 (anyone want a project?)
    1981 GPZ 550 (backroad screamer)
    1970 450 Mk IIID (THUMP!)
    2007 DRz 400S
    1999 ATK 490ES
    1994 DR 350SES

    Comment


      #3
      Just a reminder - APE pods look and perform every bit as good as K&N's for half the price.
      1982 GS1100E V&H "SS" exhaust, APE pods, 1150 oil cooler, 140 speedo, 99.3 rear wheel HP, black engine, '83 red

      2016 XL883L sigpic Two-tone blue and white. Almost 42 hp! Status: destroyed, now owned by the insurance company. The hole in my memory starts an hour before the accident and ends 24 hours after.

      Comment


        #4
        Originally posted by Big T View Post
        Fuel - 7/8
        Air - 1 1/2
        Also, bench sync them before reinstalling
        Thank you, I will try these settings! Funny I literally just came across a semi-related thread with many paragraphs of text that had the same suggestion with a semi-similar bike using the VM carbs.
        78' GS750

        Comment


          #5
          Originally posted by Rob S. View Post
          Just a reminder - APE pods look and perform every bit as good as K&N's for half the price.
          good to know, thanks!
          78' GS750

          Comment


            #6
            Get rid of those horrible cheap Emgo pods.
            They are well known for being restrictive and will strangle the motor.
            Start with good quality free flowing pods such as APE,K&N, Uni filter etc .
            Leave all other carb settings stock apart for going up a couple of sizes on the mains and fit air corrector jets to cure the off idle hesitation/rough running..
            Air corrector jet kit. Suzuki GS1000,GS850,GS750.MIKUNI.LEDAR.PODS,K&N,FILTERS. | eBay
            Last edited by zed1015; 07-07-2021, 06:31 AM.
            Mikuni Viton Choke Plunger Seat Renewal.
            VITON Choke plunger seals .KAWASAKI Z1,Z900,Z650,Z1000,Z1R,SUZUKI GS1000,GSXR,RF | eBay

            Air Corrector Jets for Mikuni VM 24, 26 and 28mm carbs .
            https://www.ebay.co.uk/itm/254380193...84.m1555.l2649



            sigpic

            Comment


              #7
              Update: Got all 4 cylinders to fire with 7/8 fuel screw out and 1.5 air! It idled ok and had response on the throttle, which was awesome. After it warmed up a bit and I missed with choke and idle screw it died. I'll continue to tweak and tune, it still feels lean to me...

              Also, took a temp reading and 2 outside cylinders reading 280 degrees and 2 inside reading 250...seems a bit warm after only idling for a minute or two, thinking still lean, thoughts? Fuel screw out another 1/4 turn or air screw in another 1/4-1/2 turn?
              78' GS750

              Comment


                #8
                The screws only affect the idle mixture

                You tune that with high idle, or a Colortune
                1978 GS 1000 (since new)
                1979 GS 1000 (The Fridge, superbike replica project)
                1978 GS 1000 (parts)
                1981 GS 850 (anyone want a project?)
                1981 GPZ 550 (backroad screamer)
                1970 450 Mk IIID (THUMP!)
                2007 DRz 400S
                1999 ATK 490ES
                1994 DR 350SES

                Comment


                  #9
                  Originally posted by Big T View Post
                  The screws only affect the idle mixture

                  You tune that with high idle, or a Colortune
                  So, I tried to go at them with colortune today...with no success. Cylinder 1 intially showed me a blueish/whiteish light, and then it faded away. The cylinder stayed warm but definitely wasn't firing like it should be....so....not sure what to do about that. Messing with air screw while colortune in didn't have any affect. Cylinder 4 same result. This is with idle at around 1100rpm, are you saying that I need to jack that way up in order to get a reading?
                  78' GS750

                  Comment


                    #10
                    Originally posted by wired137 View Post
                    Thank you, I will try these settings! Funny I literally just came across a semi-related thread with many paragraphs of text that had the same suggestion with a semi-similar bike using the VM carbs.
                    ****** QUOTE ******
                    Originally Posted by Big T
                    Fuel - 7/8
                    Air - 1 1/2
                    Also, bench sync them before reinstalling. ****** UNQUOTE ******

                    The most important thing said above was, "bench synch them before reinstalling.

                    You will get no where without doing that. If you don't know exactly what that is and how to do it say so now.
                    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
                      Originally posted by wired137 View Post
                      So, I tried to go at them with colortune today...with no success. Cylinder 1 intially showed me a blueish/whiteish light, and then it faded away. The cylinder stayed warm but definitely wasn't firing like it should be....so....not sure what to do about that. Messing with air screw while colortune in didn't have any affect. Cylinder 4 same result. This is with idle at around 1100rpm, are you saying that I need to jack that way up in order to get a reading?
                      The 1100 rpm idle is spot on
                      High idle method involves tweaking each air screw to its highest idle
                      Something's wrong if your mixture readings are fluctuating
                      1978 GS 1000 (since new)
                      1979 GS 1000 (The Fridge, superbike replica project)
                      1978 GS 1000 (parts)
                      1981 GS 850 (anyone want a project?)
                      1981 GPZ 550 (backroad screamer)
                      1970 450 Mk IIID (THUMP!)
                      2007 DRz 400S
                      1999 ATK 490ES
                      1994 DR 350SES

                      Comment


                        #12
                        Your pilot is way too rich at 20, back it off to 15 stock you'll be fine.
                        -Mal

                        "The only reason for time is so that everything doesn't happen at once." - B. Banzai
                        ___________

                        78 GS750E

                        Comment


                          #13
                          Originally posted by earlfor View Post
                          ****** QUOTE ******
                          Originally Posted by Big T
                          Fuel - 7/8
                          Air - 1 1/2
                          Also, bench sync them before reinstalling. ****** UNQUOTE ******

                          The most important thing said above was, "bench synch them before reinstalling.

                          You will get no where without doing that. If you don't know exactly what that is and how to do it say so now.
                          yep bench sync'd would like to vaccuum sync but don't have tool just yet
                          78' GS750

                          Comment


                            #14
                            Originally posted by allojohn View Post
                            Your pilot is way too rich at 20, back it off to 15 stock you'll be fine.
                            any chance that is putting some excess fuel in my exhaust
                            78' GS750

                            Comment


                              #15
                              Originally posted by wired137 View Post
                              any chance that is putting some excess fuel in my exhaust
                              Maybe.... you also need to lower the e-clip on the needle two spaces. There are a few of on here running '78 750's (pods) with these settings.
                              -Mal

                              "The only reason for time is so that everything doesn't happen at once." - B. Banzai
                              ___________

                              78 GS750E

                              Comment

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