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79 GS850 to 80 head swap

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    79 GS850 to 80 head swap

    Swapping a 80+ head onto a 79 engine. What gaskets do I use?

    80+ or 79-78 ?

    Dear wife has graciously given me a rebuild as a Christmas gift.

    #2
    Gaskets are different?
    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

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      #3
      Check the part numbers on the Alphasports web site for the 79 and 80 to confirm

      The internal gaskets should be the same

      The carb intakes are different

      I just have to ask, why are you swapping heads?
      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


        #4
        All the gaskets are the same.

        But the intakes, carbs, etc. are very different...
        1983 GS850G, Cosmos Blue.
        2005 KLR685, Aztec Pink - Turd II.3, the ReReReTurdening
        2015 Yamaha FJ-09, Magma Red Power Corrupts...
        Eat more venison.

        Please provide details. The GSR Hive Mind is nearly omniscient, but not yet clairvoyant.

        Celeriter equita, converteque saepe.

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        Co-host of "The Riding Obsession" sport-touring motorcycling podcast at tro.bike!

        Comment


          #5
          Originally posted by Big T View Post
          I just have to ask, why are you swapping heads?
          Unless he has some mechanical defect, the only advantage I could see is that he gets the larger intake ports of the CV-type carbs.

          All of the gaskets should be the same. They did not change until '82, when they added three bolts to the valve cover.
          One other change for '82 was the clutch cover. There is a squarer back end on it where the hump was removed from where the kick starter used to be.

          86turbodsl, are you also aware that the intake cams are different from '79 to '80?
          The exhaust cam timing is the same, but the intake opens and closes 10 degrees earlier on the '80.

          .
          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
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          Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
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          Comment


            #6
            Thanks for the info guys.

            To shed some light on the subject, I recieved the bike with a head that had a few broken studs. The quote to fix/remove the broken studs (EDM) was more than the cost of a replacement Ebay head and carbs in good shape.

            So what gaskets do I need?

            Base (cylinder is off)
            Head
            Valve
            O rings
            Anything else?

            I think I only have the 79 cams. That should drop in though.

            Comment


              #7
              Originally posted by 86turbodsl View Post
              So what gaskets do I need?

              Base (cylinder is off)
              Head
              Valve
              O rings
              Anything else?
              Valve seals
              Cam Chain tensioner gasket
              Breather gasket
              Exhaust gaskets

              May as well just buy a full gasket set. Be cheaper and easier
              1979 GS750E

              Comment


                #8
                Base O rings (okay, pear shaped)

                Intake O rings

                Cam chain guides as needed

                Air box

                Throttle cables (?)
                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
                  Hmm. Wondered about throttle cables. Anyone know for sure?

                  The later carbs are in really good shape.

                  Comment


                    #10
                    I have had the stock 26's, 34 CV's and 29 smoothbores on the same bike and never had to change the cables.
                    Does that answer your question?

                    Daniel

                    Comment


                      #11
                      Yup. Thanks!

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