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CV carbs vs mechanically activated slides

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    CV carbs vs mechanically activated slides

    Im wondering if anyone updates their old gs bikes with later model CV carbs.

    I have my '79 gs1000 running pretty good with the stock VM 26's jetted for pods and a 4:1 (& my own muffler thing which has no muff but employs an antireversion cone for transition and s reducer at the outlet, idk what I was thinking but it works well). I also put tubes in the pods and taped off some of the outside surface.. I went I think 2 clicks up on the mains and stock pilots (I have the next size up pilots (17.5 from 15's?) I might try but it's running pretty good except for a lug at slow roll on from a stop (seems to want a goose and snappy clutch work).

    Back to my post.. so before I got the gs1000 dialed in I got a set of bst33's from a katana600 I parted and then also a set of bst36's from a kat750 and I WAS thinking about trying the bst33's. So that's just brewing in my head (I know I would need some slick adapter manifolds, ideas?)..

    I just found a set of tk26 CV carbs (cheap) from an early 80's kz550 and was wondering if these might be desireable to the kz community or adaptable for a gs750 (i have vm26's on that gs750 now with pods running ok). Checking on ebay, seems more of the mechanical slide vm's and keihin are sold for UJM's.

    Thoughts??
    1979 gs1000e (everyday) 1977 gs750 for sale
    1983 yam xj550 maxim streetbob sold
    1995 gsx750F everyday fighterjet 1990 gsx1100F for sale
    2000kaw zx600
    2003 BMW K1200GT sport tour
    2000Buel Cyclone M2 motorwork
    1984 Yam venture xvz1200 -long ride/cold ride ride gf ride..
    1978 Honda cb750F3 supersport top end (still)
    1976 Harley FL 3/8" S&S stroker - motor out way too long
    1980 Harley fxs80 - wacked good on this one

    #2
    To properly adapt to CV-style carbs, you will need to have adapters, because the CV-style carbs are larger. For example, newer versions of your 1000 have BS34SS carbs, the 26s you mention are simply too small. In fact, the GS550 through the GS850 all use BS32SS carbs.

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    Comment


      #3
      Take the tape off the pod filters, you're robbing the engine of airflow which is one of the reasons pods are put on in the first place. Put your stock pilot jet back in, 17.5's are often too big. Try 15's with the fuel screw turned 1.5 out from the bottom. Then up the main jet substantially, sometimes 5 sizes over stock is necessary if not more. Once that is sorted, adjust your needle clip position down one.

      That should get you close.

      Comment


        #4
        Sounds like a lot of work for zero gain

        Remember the VM 26s and BS 34s deliver the same HP and are equivalent in air flow

        Plus, the BS carbs are a lot harder to tune for pods and it seems you don't have that dialed in yet in your current configuration
        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


          #5
          Thanks Steve. I wasn't thinking of trying the TK 26's on my GS1000 but rather will I find KZ550 owners that want them over round slides/. And as for the BST33's, 34's or 36's on my GS1000 do any make sense over the VM26's and if so, do you know which adapters bolt on?

          Originally posted by Steve View Post
          To properly adapt to CV-style carbs, you will need to have adapters, because the CV-style carbs are larger. For example, newer versions of your 1000 have BS34SS carbs, the 26s you mention are simply too small. In fact, the GS550 through the GS850 all use BS32SS carbs.

          .
          1979 gs1000e (everyday) 1977 gs750 for sale
          1983 yam xj550 maxim streetbob sold
          1995 gsx750F everyday fighterjet 1990 gsx1100F for sale
          2000kaw zx600
          2003 BMW K1200GT sport tour
          2000Buel Cyclone M2 motorwork
          1984 Yam venture xvz1200 -long ride/cold ride ride gf ride..
          1978 Honda cb750F3 supersport top end (still)
          1976 Harley FL 3/8" S&S stroker - motor out way too long
          1980 Harley fxs80 - wacked good on this one

          Comment


            #6
            Thanks, Special K, just found some old notes about the pilots and mix screw. and if I can understand what I wrote, seems it came with 20 pilots and I tried several mix settngs, then did same with the 15 pilots and somewhere in there I bought 17.5's but never installed them as it ran pretty good after the pod mods/. Looks like I ended at 1.5 turn fuel ad 2.75 turns air mix. all this was after going way up on the mains (I think I started 1 click up from stock and went up another 4 jet sizes. and I'm not sure how much airflow I'm "robbing" considering the exposed area compared to the stock airbox
            opening and that it seemed to lean in the midrange before that and it seems to run pretty good now
            Originally posted by SpecialK View Post
            Take the tape off the pod filters, you're robbing the engine of airflow which is one of the reasons pods are put on in the first place. Put your stock pilot jet back in, 17.5's are often too big. Try 15's with the fuel screw turned 1.5 out from the bottom. Then up the main jet substantially, sometimes 5 sizes over stock is necessary if not more. Once that is sorted, adjust your needle clip position down one.

            That should get you close.
            1979 gs1000e (everyday) 1977 gs750 for sale
            1983 yam xj550 maxim streetbob sold
            1995 gsx750F everyday fighterjet 1990 gsx1100F for sale
            2000kaw zx600
            2003 BMW K1200GT sport tour
            2000Buel Cyclone M2 motorwork
            1984 Yam venture xvz1200 -long ride/cold ride ride gf ride..
            1978 Honda cb750F3 supersport top end (still)
            1976 Harley FL 3/8" S&S stroker - motor out way too long
            1980 Harley fxs80 - wacked good on this one

            Comment


              #7
              good points Big T.. I didn't know how the BST33's or BST34's faired against the VM26's or if the BST 36's would add any performance or streetability. Right now unless I get my Kat1100 BST34's working right, the BST36's might go on the Kat 11. Again,the point of my post was those TK26 CV carbs - sellable or garbage... (I assumed too small for my G1000 bc they came off a KZ550 (unless jets would do it)
              1979 gs1000e (everyday) 1977 gs750 for sale
              1983 yam xj550 maxim streetbob sold
              1995 gsx750F everyday fighterjet 1990 gsx1100F for sale
              2000kaw zx600
              2003 BMW K1200GT sport tour
              2000Buel Cyclone M2 motorwork
              1984 Yam venture xvz1200 -long ride/cold ride ride gf ride..
              1978 Honda cb750F3 supersport top end (still)
              1976 Harley FL 3/8" S&S stroker - motor out way too long
              1980 Harley fxs80 - wacked good on this one

              Comment


                #8
                Hmm, are you talking about the fuel mix screw setting, or the air mix screw s?

                Yes, the TKs are way too small for a 1000
                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
                  Fuel screw and air screw

                  I listed my final setting on the fuel mix and the air mix with seems to indicate that my pilots are aboutf right sized

                  Originally posted by Big T View Post
                  Hmm, are you talking about the fuel mix screw setting, or the air mix screw s?

                  Yes, the TKs are way too small for a 1000
                  1979 gs1000e (everyday) 1977 gs750 for sale
                  1983 yam xj550 maxim streetbob sold
                  1995 gsx750F everyday fighterjet 1990 gsx1100F for sale
                  2000kaw zx600
                  2003 BMW K1200GT sport tour
                  2000Buel Cyclone M2 motorwork
                  1984 Yam venture xvz1200 -long ride/cold ride ride gf ride..
                  1978 Honda cb750F3 supersport top end (still)
                  1976 Harley FL 3/8" S&S stroker - motor out way too long
                  1980 Harley fxs80 - wacked good on this one

                  Comment

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