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    VM Carb Choke Pickup Tube Replacement

    Not sure if this was covered before but... here it goes.

    Had 4x cracked choke pickup tubes on my 77 GS550 carbs. Was annoyed, because I had acquired a 500 mile bike and was hoping it'd be in better condition. I saw a modeling video on YT and thought - that's some really small brass tube. 5 minutes on Amazon found a pack of 3mm OD x 2.5mm ID tube and some 2.5mm OD brass rods. Tossed in a micro drill set and... a few bucks later... I was making my own VM replacement brass parts.

    So, I cut the tube to length 32.5mm (I think) and soldered in a piece of the rod for a plug. Cut off the rod and bam - tube with a plug. 5 min with the micro drill and I had this.

    I have to say - it's the same length and diameter as the original. The wall thickness is NOT the same but I didn't find any replacement bits, so I feel pretty good about my first go at homemade carb parts. I'll report back on how it works once I get everything put back together.
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    Last edited by OldPainless; 06-05-2024, 09:55 PM.

    #2
    And a shot in the carb.
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    Comment


      #3
      Nice work. Your carbs have a chalky scale on them, but the choke tubes look nice!
      Ed

      To measure is to know.

      Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

      Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

      Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

      KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

      Comment


        #4
        Yeah - anything I can do about the chalkiness? One is really bad looking.

        Comment


          #5
          did you soak the carbs in carb dip? That may help if you haven't. I use cheap wire brushes as sold by places like Amazon, in a dremel. That won't clean the interior passages, but at least you won't have the crud in the float bowls.
          Ed

          To measure is to know.

          Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

          Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

          Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

          KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

          Comment


            #6
            Awesome. I stopped using carb dip a while back in favor of using my sonic cleaner with aluminum safe simplegreen. I'll get some carb dip and wire brushes.

            Comment


              #7
              All you need to do for cracked tubes or overflows is simply flux and solder the seams.
              MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
              1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

              NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


              I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

              Comment


                #8
                Originally posted by chuck hahn View Post
                All you need to do for cracked tubes or overflows is simply flux and solder the seams.
                Sorry, chuck, but I disagree. Replacing them is far better.
                Ed

                To measure is to know.

                Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

                Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

                Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

                KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

                Comment


                  #9
                  Soldering hurts nothing. Reseal the seam and be done with it forever
                  MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                  1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                  NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                  I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                  Comment


                    #10
                    Except when you go to solder it and they crumble away...

                    Tried that first. Wouldn't be engineering a solution this elaborate if the obvious worked. Plus - it gives me something to do.

                    Comment


                      #11
                      Well yeah but i didnt gather that detail from the post. As for the chalky scale. Iwould try soaking one in 8 percent cleaning vinegar.That might eat it away. I also have used those wire brushes for y Dremel to scrub them..Sometimes even that doesnt get it all but it will get anything that could flake off gone for sure
                      MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                      1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                      NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                      I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                      Comment


                        #12
                        Keihin carb overflow tubes commonly split. I messed around with soldering, but wasn't happy with how it was turning out, so I taught myself how to replace the tubes. The biggest challenge was flaring the OD of the tube, so the press fit will seal. I took a drill bit of appropriate size, ground a taper into the butt end of the bit, and inserted it into the piece of brass tubing I found, using a drill motor. I also rolled over the end of the tube using the dimple in a threading die. This part didn't work out perfectly, though. At any rate, I've done at least a dozen bowls this way now with good results.

                        P1030567 by nessism, on Flickr
                        Ed

                        To measure is to know.

                        Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

                        Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

                        Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

                        KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

                        Comment


                          #13
                          I have replaced those without flairing the tubing. I put some tank sealer on the tube and spun it around to distribute the sauce. Dozens of ways to skin the cat.
                          MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                          1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                          NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                          I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                          Comment

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