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Pod type filters for VM 30 carbs on GS 1000 ST ( European/Australian spec)

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    #16
    Following an advice on the french GS forum, I went for 137.5 main jets.
    The bike now runs fine from 1/4 throttle to full throttle.
    I'll have to do a plug chop to fine tune further.
    The engine also pops under deceleration and the idle is quite lumpy.
    I suppose, I will need to resynch the carbs following moving the needles two slots up.
    sigpicJohn Kat
    My bikes: CB 77, GS 1000 ST Cafe Racer with GSXR 1052 engine, GS 1000 ST, XR 41 Replica with GS 1085 engine,
    GS 1100 SZ Katana with GS 1135 EFF engine, KTM Superduke 1290 R 2020

    Comment


      #17
      Originally posted by John Kat View Post
      Following an advice on the french GS forum, I went for 137.5 main jets.
      Sounds about right, as i said earlier i run 130's on 29mm smoothies.
      try upping the pilots a size and see how it runs then.
      1978 GS1085.

      Just remember, an opinion without 3.14 is just an onion!

      Comment


        #18
        Originally posted by Agemax View Post
        Sounds about right, as i said earlier i run 130's on 29mm smoothies.
        try upping the pilots a size and see how it runs then.
        I'll try that if synching the carbs doesn't help.
        sigpicJohn Kat
        My bikes: CB 77, GS 1000 ST Cafe Racer with GSXR 1052 engine, GS 1000 ST, XR 41 Replica with GS 1085 engine,
        GS 1100 SZ Katana with GS 1135 EFF engine, KTM Superduke 1290 R 2020

        Comment


          #19
          Hi John, have been away as Greg said- 3 days on some of NZ's best motorcycle roads!
          My regular riding companions still are amazed at how well a '80 1000S can still hustle! Managed a first place in front of my mate on his '05 GSXR750 over the famous (in NZ) Takaka hill. 25 km each way of M/C paradise!! One of those hills you want to turn around and ride again- so we did!

          Anyway, to the point; Main jets on my VM 30s- 107.5 (up from 97,5). Needles- can't remember what groove, but std size.Pilots- ended up with 25's. Ran like a pig until I got the pilots sorted! Floats set at std (24.5?) GS` runs cleanly through idle to redline and will handle gas from 91-98 octane equally well
          Pipe is a local 4:1 with CF muffler, airbox std with KN.
          I tune the carbs using a 'colortune', and balance with an old set of vacuum gauges. The std vac fuel tap works fine. As Greg intimated, there is only one hose that is vacuum- the rest are overflows; can't remember, but I think the takeoff is between #3 &4? It's noted somewhere in the forum.
          Oh! Also, John, I softened up my rubbers with a lanolin cream (we have lots of it here- more sheep in NZ than people!) I would be happy to post you a tub if you can't get any in France! Cheers, Adrian

          Comment


            #20
            Originally posted by kiwimacchi View Post
            Hi John, have been away as Greg said- 3 days on some of NZ's best motorcycle roads!
            My regular riding companions still are amazed at how well a '80 1000S can still hustle! Managed a first place in front of my mate on his '05 GSXR750 over the famous (in NZ) Takaka hill. 25 km each way of M/C paradise!! One of those hills you want to turn around and ride again- so we did!

            Anyway, to the point; Main jets on my VM 30s- 107.5 (up from 97,5). Needles- can't remember what groove, but std size.Pilots- ended up with 25's. Ran like a pig until I got the pilots sorted! Floats set at std (24.5?) GS` runs cleanly through idle to redline and will handle gas from 91-98 octane equally well
            Pipe is a local 4:1 with CF muffler, airbox std with KN.
            I tune the carbs using a 'colortune', and balance with an old set of vacuum gauges. The std vac fuel tap works fine. As Greg intimated, there is only one hose that is vacuum- the rest are overflows; can't remember, but I think the takeoff is between #3 &4? It's noted somewhere in the forum.
            Oh! Also, John, I softened up my rubbers with a lanolin cream (we have lots of it here- more sheep in NZ than people!) I would be happy to post you a tub if you can't get any in France! Cheers, Adrian
            Hi Adrian,
            Many thanks for the feedback!
            I've compounded the issue as I'm running with APE pods ( those made for 1st gen GSXR's).
            The 137.5 mains are working well, the issue is only the idle running like a pig as you say.
            Did you have to resynch the carbs after changing the position of the needle?
            My pilots are currently 22.5's.
            If the synch is OK I'll go for 25's or 27.5's.
            You are right about the way the GS 1000 S performs.
            A couple of years back, I lent my modern Kawasaki ZX 1000 to a friend and I took the GS.
            He couldn't quite believe the pace we were riding at...
            sigpicJohn Kat
            My bikes: CB 77, GS 1000 ST Cafe Racer with GSXR 1052 engine, GS 1000 ST, XR 41 Replica with GS 1085 engine,
            GS 1100 SZ Katana with GS 1135 EFF engine, KTM Superduke 1290 R 2020

            Comment


              #21
              Hi John, yes, the carbs seem to go out of sync everytime you look at something!

              Bit painful, but it gets easier......

              Comment


                #22
                I got my 27.5 pilot jets today and the idle is much better allthough not perfect.
                I'll balance the carbs next to try to fix that.
                In any case the bike is now rideable with a nice transition between 1/8 to 1/2 throttle and pulling very strongly.
                It will not take full throttle yet but I don't know if it's too rich or too lean?
                If I reduce the throttle a little, the bike picks up more revs.
                sigpicJohn Kat
                My bikes: CB 77, GS 1000 ST Cafe Racer with GSXR 1052 engine, GS 1000 ST, XR 41 Replica with GS 1085 engine,
                GS 1100 SZ Katana with GS 1135 EFF engine, KTM Superduke 1290 R 2020

                Comment


                  #23
                  Hi John,

                  I've got a 1100SXZ Kat wire wheeler with the VM32SS carb set. Currently running an open (no aircleaner box) foam uni-filter clamped to the front airbox/plenum chamber with a 4 into 1 pipe. This is airbox filter arrangement is my favourite set up as you retain the velocity stacks that are part of the airbox to carb hoses, and the resonance and airflow stability provided by the plenum chamber, and get increased air flow at WFO. I've used K&N pods, but didn't really them. it would run rich if it rained because the out pods got wet... I used to use a K&N on the end of the plenum, but now have my doubts on the filtration efficiency of oiled cotton gauze.

                  The standard mains are 102.7 and were upgraded to 117.5 to deal with increase in top end air flow. I started with much larger mains (130s I think) which gave me sooty plugs, downsized to 125s, then a step at a time, checking plug colour by doing WFO plug chops late at night in 3rd gear up a hill on the North Western motorway until I got nice tan plugs. You have to do WFO plug chops, unless you fit a lambda probe and measure the AF ratio through a gauge of some sort. You won't know if your a jet size or two too rich or too lean on the mains through the seat of your pants.

                  I lifted the needle one clip, again testing with a plug chop at half throttle.

                  The VMs used on Suzuki's also offer a lot of idle/slow/pilot circuit adjustment having both an air screw and fuel (or sometimes called the mixture) screw. Someone on here called them the 'side screw' and 'bottom screw' which is a good way to differentiate them. The bottom screw usually comes with dire warning about disturbing them as they were set at the factory using special equipment... Which isn't handy if you have to do a complete tear down and clean them as part of a full restoration.




                  The screws aren't shown on the microfiche, but they're there and visible at the front of the carb bowls.

                  Generally the best way to approach the VM idle/slow/pilot circuit is to try to correct by adjustment before swapping pilot jets. Once you've determined that the you can't enrichen or lean it out enough through the screws, then look to go up or down a pilot jet size and test again. The best way to adjust the screws is using a colortune plug. I usually post on another Katana related website which isn't visible to the public, but I've re-posted my VM pilot/slow tuning from this site into this thread
                  http://www.thegsresources.com/_forum/showthread.php?229451-gs750-carbs-are-killin-me/page3

                  You really need to check the mixture via the plugs and/or a colortune, otherwise it's just best guess, and possibly not best carburation.

                  ...incidentally, you only need to re-synch the carbs if the you've removed the throttle shaft.
                  Last edited by KiwiAlfa156; 04-26-2017, 01:40 AM.
                  sigpicDarryl from Kiwiland

                  1982 GSX1100S Katana
                  1982 GSX750S Katana
                  1982 GS650G Katana

                  Comment


                    #24
                    Originally posted by KiwiAlfa156 View Post
                    Hi John,

                    I've got a 1100SXZ Kat wire wheeler with the VM32SS carb set. Currently running an open (no aircleaner box) foam uni-filter clamped to the front airbox/plenum chamber with a 4 into 1 pipe. This is airbox filter arrangement is my favourite set up as you retain the velocity stacks that are part of the airbox to carb hoses, and the resonance and airflow stability provided by the plenum chamber, and get increased air flow at WFO. I've used K&N pods, but didn't really them. it would run rich if it rained because the out pods got wet... I used to use a K&N on the end of the plenum, but now have my doubts on the filtration efficiency of oiled cotton gauze.

                    The standard mains are 102.7 and were upgraded to 117.5 to deal with increase in top end air flow. I started with much larger mains (130s I think) which gave me sooty plugs, downsized to 125s, then a step at a time, checking plug colour by doing WFO plug chops late at night in 3rd gear up a hill on the North Western motorway until I got nice tan plugs. You have to do WFO plug chops, unless you fit a lambda probe and measure the AF ratio through a gauge of some sort. You won't know if your a jet size or two too rich or too lean on the mains through the seat of your pants.

                    I lifted the needle one clip, again testing with a plug chop at half throttle.

                    The VMs used on Suzuki's also offer a lot of idle/slow/pilot circuit adjustment having both an air screw and fuel (or sometimes called the mixture) screw. Someone on here called them the 'side screw' and 'bottom screw' which is a good way to differentiate them. The bottom screw usually comes with dire warning about disturbing them as they were set at the factory using special equipment... Which isn't handy if you have to do a complete tear down and clean them as part of a full restoration.




                    The screws aren't shown on the microfiche, but they're there and visible at the front of the carb bowls.

                    Generally the best way to approach the VM idle/slow/pilot circuit is to try to correct by adjustment before swapping pilot jets. Once you've determined that the you can't enrichen or lean it out enough through the screws, then look to go up or down a pilot jet size and test again. The best way to adjust the screws is using a colortune plug. I usually post on another Katana related website which isn't visible to the public, but I've re-posted my VM pilot/slow tuning from this site into this thread
                    http://www.thegsresources.com/_forum/showthread.php?229451-gs750-carbs-are-killin-me/page3

                    You really need to check the mixture via the plugs and/or a colortune, otherwise it's just best guess, and possibly not best carburation.

                    ...incidentally, you only need to re-synch the carbs if the you've removed the throttle shaft.
                    Hi Darryl,

                    Your input is most appreciated!
                    The main reason for me going to pods is because the rubber hose going from one of the carbs to the airbox has split open.
                    As I believe these are no longer available I decided to go down the pod road...
                    So far, I can't believe the extra noise it generates, far worse than the pods fitted on another GS 1000 with CV carbs?
                    I'll definitely try your pilot tuning method.
                    Many thanks
                    John
                    sigpicJohn Kat
                    My bikes: CB 77, GS 1000 ST Cafe Racer with GSXR 1052 engine, GS 1000 ST, XR 41 Replica with GS 1085 engine,
                    GS 1100 SZ Katana with GS 1135 EFF engine, KTM Superduke 1290 R 2020

                    Comment


                      #25
                      You can get them on eBay

                      THESE ARE CURRENT PRODUCTION PARTS AND ARE SOFT AND FLEXIBLE LIKE NEW PARTS SHOULD BE. THESE ARE THE BOOTS WHICH CONNECT THE CARBURETORS TO THE AIR BOX. LAST IMAGE IS FOR REFERENCE TO SHOW WHERE PARTS ARE LOCATED ON THE BIKE.


                      Or Partzilla

                      Buy Suzuki 13881-49021 - OUTLET TUBE. This OEM part is guaranteed by Suzuki's limited part warranty ✓ FREE Shipping on qualified orders - Partzilla.com


                      Or closer to home CMS

                      ✓Get the TUBE,AIR CLEANER OUTLET ✓Manufacturercode: 13881-49200 ✓Genuine Suzuki part
                      Last edited by KiwiAlfa156; 04-26-2017, 04:50 AM.
                      sigpicDarryl from Kiwiland

                      1982 GSX1100S Katana
                      1982 GSX750S Katana
                      1982 GS650G Katana

                      Comment


                        #26
                        Originally posted by KiwiAlfa156 View Post
                        You can get them on eBay

                        THESE ARE CURRENT PRODUCTION PARTS AND ARE SOFT AND FLEXIBLE LIKE NEW PARTS SHOULD BE. THESE ARE THE BOOTS WHICH CONNECT THE CARBURETORS TO THE AIR BOX. LAST IMAGE IS FOR REFERENCE TO SHOW WHERE PARTS ARE LOCATED ON THE BIKE.


                        Or Partzilla

                        Buy Suzuki 13881-49021 - OUTLET TUBE. This OEM part is guaranteed by Suzuki's limited part warranty ✓ FREE Shipping on qualified orders - Partzilla.com


                        Or closer to home CMS

                        https://www.cmsnl.com/products/13881.../#.WQBfELh96M8
                        I'm afraid they are the wrong size for the GS 1000 ST as my carbs measure 49 mm O.D. on the intake side vs 55 mm for these that are designed for CV carbs.
                        In the meantime I checked my carb balance that was far off until I remembered to block off the vacuum source on the N°3...
                        The idle is not perfect yet so I'll have to invest in a colortune spark plug!
                        sigpicJohn Kat
                        My bikes: CB 77, GS 1000 ST Cafe Racer with GSXR 1052 engine, GS 1000 ST, XR 41 Replica with GS 1085 engine,
                        GS 1100 SZ Katana with GS 1135 EFF engine, KTM Superduke 1290 R 2020

                        Comment


                          #27
                          Do you have the Suzuki part number John?
                          sigpicDarryl from Kiwiland

                          1982 GSX1100S Katana
                          1982 GSX750S Katana
                          1982 GS650G Katana

                          Comment


                            #28
                            Ah, there is no part number.... its part of the airbox... which is unavailable....
                            sigpicDarryl from Kiwiland

                            1982 GSX1100S Katana
                            1982 GSX750S Katana
                            1982 GS650G Katana

                            Comment


                              #29
                              Originally posted by KiwiAlfa156 View Post
                              Ah, there is no part number.... its part of the airbox... which is unavailable....
                              I had the OEM part number from the origninal GS 1000 ST microfiche but when I ordered the part I got a boot for some other Suzuki model...
                              I believe Suzuki reused some of the GS 1000 ST PN's for other models!
                              sigpicJohn Kat
                              My bikes: CB 77, GS 1000 ST Cafe Racer with GSXR 1052 engine, GS 1000 ST, XR 41 Replica with GS 1085 engine,
                              GS 1100 SZ Katana with GS 1135 EFF engine, KTM Superduke 1290 R 2020

                              Comment


                                #30
                                I finally took the time to tune the idle settings on my carbs today.
                                After balancing the carbs, I used the Gunson colortune spark plug to determine if the AFR ratio was correct.
                                This device is very usefull as after changing the pilot jets one has no idea of where to set the mixture screws.
                                In fact it was far too rich with a yellow flame that turned into a nice blue color after adjustment.
                                I used the colortune spark plug only for the cylinders 1 and 4 as they are the easiest to access.
                                Cylinders 2 and 3 were done using the highest rev method.
                                The result is really great with a very smooth idle and a clean pick-up when opening the throttle.
                                The road test comes next!
                                sigpicJohn Kat
                                My bikes: CB 77, GS 1000 ST Cafe Racer with GSXR 1052 engine, GS 1000 ST, XR 41 Replica with GS 1085 engine,
                                GS 1100 SZ Katana with GS 1135 EFF engine, KTM Superduke 1290 R 2020

                                Comment

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