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    #1

    GS 850GX surges

    Hi all'

    I have an 81 GS850G that is surging while cruising at 50 - 55 mph. I have gone through the carbs, put in new plugs, foam UNI airfilter and repacked my V&H with #3 steel wool. I am also running stock jets and needles with the mixture screws 3 turns out. I have also eliminated the vacuum line for the petcock and sealed everything up tight. I know that someone else has said that their 81 GS850G ran well with 120 main jets. can anyone help shed some light on this?

    Thanks,
    Scott
    Tags: None
    #2
    Originally posted by scottsgs View Post
    ... someone else has said that their 81 GS850G ran well with 120 main jets.
    That might have been ... err ... well ... ummm ... me.

    We have gotten my son's '81 850G together and running quite well. I can't remember how many turns out the mixture screws are, but there are 120 mains in there. All other jets are stock. Stock airbox with K&N insert, unknown header (looks like a MAC, but has a different silencer than I have seen before), baffle is wrapped with #3 steel wool (you couldn't find #4 either?).

    As soon as we get the bike title officially transferred and registered, I will be taking longer rides to get a better feel for how it runs. TheCafeKid has also felt that jetting is pretty close, if not actually spot-on.



    .
    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

      #3
      Originally posted by scottsgs View Post
      Hi all'

      I have an 81 GS850G that is surging while cruising at 50 - 55 mph. I have gone through the carbs, put in new plugs, foam UNI airfilter and repacked my V&H with #3 steel wool. I am also running stock jets and needles with the mixture screws 3 turns out. I have also eliminated the vacuum line for the petcock and sealed everything up tight. I know that someone else has said that their 81 GS850G ran well with 120 main jets. can anyone help shed some light on this?

      Thanks,
      Scott
      Why??




      .......

      Comment

        #4
        So you're running on prime?
        Surging is usually lean. Probably lean on the needle.
        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

          #5
          Originally posted by Steve View Post
          We have gotten my son's '81 850G together and running quite well.
          .
          that looks like a nice job, steve
          i remember the pic the day you got that bike - sure looked a bit tired back then, eh?
          GS850GT

          Comment

            #6
            Yeah. We have a few more touches to finish up, then I will post 'before and after' pics.

            Actually, it will be more of 'then and now' pics because he still wants to get it painted. THEN you won't recognize the bike.

            .
            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

              #7
              Cafekid,

              I removed the vacuum line on the #2 carb because I had gas being sucked in. I found the thread for this on this site, so, I thought I would try it before I spent the money. Are the needles adjustable in these carbs? If so how?

              Thanks

              Scott

              Comment

                #8
                The needles can be raised by reducing the thickness of the spacer on TOP of the needle clip. Many people positive results by removing the plastic spacer and replacing with a metal washer stack about 1/2 as thick. Do a search in the archives for more information. Also, I'd up the main as well just to be safe due to the header leaning out the mixture. The GS bikes were all lean from stock and you made it leaner with the exhaust.

                Good luck.
                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
                  Originally posted by scottsgs View Post
                  Cafekid,

                  I removed the vacuum line on the #2 carb because I had gas being sucked in. I found the thread for this on this site, so, I thought I would try it before I spent the money. Are the needles adjustable in these carbs? If so how?

                  Thanks

                  Scott
                  If gas was being sucked in, you have a faulty petcock. Replace THAT, before you start messing with the carbs.

                  Comment

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