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Gas flowing out of carb overflow tubes

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    Gas flowing out of carb overflow tubes

    Earlier I wrote about an issue that I had with my carbs dripping. I thought it might be the float needles and seat. After the bike sat a little gas would accumulate on the bottom of the bowls.

    I took the carbs off, looked them over, took out the needles and seats, and put everything back. Before I put the carbs back on the bike, I set up a rig and tested the carbs by flowing some gas in the fuel line. I tried to get them to leak, but I couldn't.

    I just put the carbs back on. Bike started right up. Then all of a sudden I had gas shooting out of the carb over flow tubes. In retrospect I think I may have crimped or pinched off the overflow tubes slight running them through a zip tie. This may have been why I had excess gas running out of the carbs.

    Is this a clear sign that the floats are set too high? I set them right at 24mm per the manual.

    Any thoughts?

    Thanks!

    Rick

    #2
    well the best way to check fuel level is the PITA clear tube test. Give it a go to see where your level really is

    Comment


      #3
      did you check the float hight with the gasket still on the carb body? while the bike was running and running over did tap the carbs lightly with a screwdriver? the float needles could be stuck. also when you measured the float hight (without the gasket) did you measure from where the gasket lays of the outer lip which sets higher (should be from where the gasket lays.)? im not sure what you mean by pinched or crimped the overflow tubes. as long as they arent bent sideways or broke-off they should have nothing to do with it overflowing; it just might keep it from draing an overflow properly. maybe im misunderstanding what you meant by that. hope this helps. i have a 79 750l also and just did my carbs a few monthes back. good luck buddy, holler if i can help.

      Comment


        #4
        24?? the VM carbs are supposed to be 26mm +/- 1mm so you're a bit on the rich side... Id pull em and set them to 26mm...

        Comment


          #5
          hey cafe kid. the 24mm is from the vm carb rebuild guide. someone had said in one of the threads that it was a misprint in the manual that said 25-27mm, and that it was changed in later versions. i just cant remember who it was. ill try to find it tomorrow and post it. the memory is the first thing to go. lol.

          Comment


            #6
            Originally posted by TheCafeKid View Post
            24?? the VM carbs are supposed to be 26mm +/- 1mm so you're a bit on the rich side... Id pull em and set them to 26mm...
            Ok, so I found out it is only carb #3 that is overflowing. I tapped it a lot and shook the bike up and down, and it still squirts out carb #3 overflow.

            So, if I set them to 26 mm, that actually reduces the amount of gas flowing into the carbs? For some reason I thought it was the other way around.

            Yeah, I will take them out and set them to 26 mm. I am not sure if I am dealing with a stuck float or just a setting that is allowing too much gas in.

            Thanks!

            Rick

            Comment


              #7
              here is where i read the 24mm setting. i dont know how to transfer the info straight from the post so please excuse the presentation. it was on a thread called 1978 gs750 issue. it was started 07-03-09, and the post was #5 by nessism.

              Comment


                #8
                I have the factory manual for the 77-79 750, the clymer, and I THINK i still have a Haynes around here somewhere... ALL said 26mm +/- 1mm. Now, the spec for the 77 carbs, which are slightly different than the 78 and 79 carbs, say 26mm period. No plus or minus. I dunno if that means anything or not, but the carbs have less parts in them than the later models so i dunno if that has anything to do with it. Ive been setting my carbs to this spec. Ive never had gas leak, nor have i had a lean running issue...

                Comment


                  #9
                  Originally posted by TheCafeKid View Post
                  I have the factory manual for the 77-79 750, the clymer, and I THINK i still have a Haynes around here somewhere... ALL said 26mm +/- 1mm. Now, the spec for the 77 carbs, which are slightly different than the 78 and 79 carbs, say 26mm period. No plus or minus. I dunno if that means anything or not, but the carbs have less parts in them than the later models so i dunno if that has anything to do with it. Ive been setting my carbs to this spec. Ive never had gas leak, nor have i had a lean running issue...
                  Thanks Josh!

                  Rick

                  Comment


                    #10
                    Originally posted by ryonker View Post
                    Thanks Josh!

                    Rick
                    Hey man, did you know that you CANNOT leave that Pingel on when the bike isnt running??

                    Comment


                      #11
                      Originally posted by TheCafeKid View Post
                      I have the factory manual for the 77-79 750, the clymer, and I THINK i still have a Haynes around here somewhere... ALL said 26mm +/- 1mm. Now, the spec for the 77 carbs, which are slightly different than the 78 and 79 carbs, say 26mm period. No plus or minus. I dunno if that means anything or not, but the carbs have less parts in them than the later models so i dunno if that has anything to do with it. Ive been setting my carbs to this spec. Ive never had gas leak, nor have i had a lean running issue...
                      cool. when i pull my carbs off again i'll set them to 26mm. thanks

                      Comment

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