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    basic carb sync help

    im having a rough time getting a halfway sync. the idle wont go down with the idle screw i backed off all the sync screws still wont go down if you push down on the cable brk it goes down but pops back up soon as you let up. the cable is loose . i dont have a sync tool as of yet but would like to get it running close i have a good ear i know it wont be perfect but adleast it will run pretty good . when you move the throttle you can see #3 move before it touches # 4 same on the other side . anyone give me a hint i dont want to pull the carbs and airbox again .once i get it to idle with the screw can fine tune it for the time being

    #2
    If you've unscrewed the balance adjusters a lot I think you're gonna have to pull the carbs again and do a bench synch. Either that or buy a set of gauges). If you've backed those screws right off you could be a mile out of synch now.
    When you do the bench synch make sure that the butterflies close fully without having to unscrew the idle screw completely.
    79 GS1000S
    79 GS1000S (another one)
    80 GSX750
    80 GS550
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    75 PC50 - the one with OHV and pedals...
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    Comment


      #3
      Originally posted by hampshirehog View Post
      When you do the bench synch make sure that the butterflies close fully without having to unscrew the idle screw completely.
      May I add that a bread twist tie, with the paper covering removed...makes a great starting spacer when placed in the carb bore between the butterflies.

      Comment


        #4
        Originally posted by cutlass79500 View Post
        im having a rough time getting ...when you move the throttle you can see #3 move before it touches # 4 same on the other side . anyone give me a hint i dont want to pull the carbs and airbox again .once i get it to idle with the screw can fine tune it for the time being
        If you can see any carb move before the others you are way out of sync. You really have to fix that first. You can do it without removing the carbs if you want to, but you might as well bite the bullet and take them off. As you gain experience pulling and reinstalling carbs you'll get better at it. Bench sync them so that all the carbs open at the same time, and by the same amount.

        If you try to do it without removing them you will have to see the butterfly valves...something that requires removal of the air box. Once you do that the carbs are almost off anyway.

        Someone here includes in his signature line 'there may not be time to do it right the first time but you will have time to do it right the second time.' or something like that. This is very true in your case. You installed them like that, now you'll have to fix it.

        Comment


          #5
          Hi Mr. cutlass79500,

          I've collected some information about carb configuration and bench syncing.

          Carb Sync Notes


          Best of luck to you.


          Thank you for your indulgence,

          BassCliff

          Comment


            #6
            Sorry, but here is yet another vote for carb removal and bench sync.

            Also need to make sure you are turning the right screws. The three carb sync screws have locknuts and are between the carbs.
            Others have turned the idle mixture screws, thinking they were the sync adjuster screws.

            By the way, I have seen some bench sync jobs that were remarkably close, requiring very little adjustment when doing the vacuum sync. Oh, and I don't think you will really be able to even get close syncing "by ear". Once you get the vacuum gauges hooked up, you can tweak one of the sync screws, see the vacuum change dramatically, and probably won't hear the faintest difference in the sound of the engine.

            .
            sigpic
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            Comment


              #7
              i know you guys are right

              i know you guys are right. but its not the answer i wanted to hear lol . i bench synced them before installing them last time the main reason i was playing with the ajustments is it has a slight miss at idle you can hear the cyl slightly popping in the exhaust . my first thought was a clogged piolet jet but if it was would not be idling at all. cant find any air leaks new orings boots . im afraid of 1 thing #4 piolet i cant get it out screw head is messed up i thought i had it cleaned but to me a plugged jet is either plugged or not shouldnt cause a slight miss at idle

              Comment


                #8
                If you couldn't get a jet out, you really have no way of telling what's behind it. If you dipped the carbs, the o-ring in that location might have partially dissolved, blocking the passage. Unless and until you get that screw out to check, you will only keep guessing what your problem is.

                .
                sigpic
                mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
                hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
                #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
                #2 son: 1980 GS1000G
                Family Portrait
                Siblings and Spouses
                Mom's first ride
                Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
                (Click on my username in the upper-left corner for e-mail info.)

                Comment


                  #9
                  passage isnt blocked carbs been soaked got a small piece of wire thru it i think spray carb cleaner in it drains out blow air thru it when i replaced the orings in the air screws. if they come off again will work it more with a wire its a really small hole in the inside end of it .will use a temp guage on the exhaust to determine for sure

                  Comment


                    #10
                    Originally posted by cutlass79500 View Post
                    ... im afraid of 1 thing #4 piolet i cant get it out screw head is messed up i thought i had it cleaned ...
                    Did you get the screw out? Unless you get the screw out, you will not know whether the o-ring around it is still intact. Sure, it might pass some carb cleaner spray and some compressed air, but what happens when it is surrounded by gas in a low-pressure, low-volume situation?

                    I repeat for emphasis ... unless you get the screw out, you won't know for sure.

                    .
                    sigpic
                    mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
                    hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
                    #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
                    #2 son: 1980 GS1000G
                    Family Portrait
                    Siblings and Spouses
                    Mom's first ride
                    Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
                    (Click on my username in the upper-left corner for e-mail info.)

                    Comment


                      #11
                      Get that pilot jet out with an easy out.
                      You got all the idle mixture screws out and replaced the o-rings, right?
                      Check and see if a clamp from the intake boots aren't jammed in the throttle linkage preventing it from closing causing the idle to hang.
                      1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
                      1985 GS1150ES stock with 85 Red E bodywork.

                      Comment


                        #12
                        Originally posted by chef1366 View Post
                        Get that pilot jet out with an easy out.
                        You got all the idle mixture screws out and replaced the o-rings, right?
                        Check and see if a clamp from the intake boots aren't jammed in the throttle linkage preventing it from closing causing the idle to hang.
                        hey chef clamps are clear going to pull the carbs and see what i can do about the jet after lunch. all orings have been replaced mixture screws are 3 turns out will let you know how it turns out

                        Comment


                          #13
                          Once the tank's off, it takes maybe 5 minutes to pull the airbox and carbs out of a shaftie. Ain't no big thang.

                          Are you working on the 850L in your sig, or some other bike?
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                          Comment


                            #14
                            Update

                            pulled the carbs bench synced them #4 there was a small peice of rubber in the jet i believe it came from the plug when i put it back in i think it shaved it a little . made a jet tool peice of mechanics wire on 1 side and a peice of wire of my wire wheel on the other side a dab of jb weld works great.
                            i guess none of the boots had time to shrink less then 2 hrs off on set and ready to ride runs great . never had to pull the jet out of #1 wich is a good thing .
                            next thing is i need to pull the tach apart the grease hardened in it doesnt6 respond properly cable ans all is fine takes a few min to return to 0 after you shut it off lol told ya it runs good thanks guys dave

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