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'81 gs1000g top end rebuild...seeking guidance.

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    '81 gs1000g top end rebuild...seeking guidance.

    Started off just trying to change my rear tire and broke off exhaust bolt in head ez out snapped as well. Now that I have it torn down I have many questions for the gurus here.
    Should I reuse the head bolts? 5 came out of the block due to rusty nuts on top.
    The cylinders look good for 28k miles. Can't catch my fingernail on piston ring lips and can see cross hatching (faintly).
    Should I replace piston rings?
    Cam lobes are under tolerance. I am sure those will have go?
    Would appreciate any and all advice as it's my first and deepest work on any bikethanks, John in south bend
    Attached Files

    #2
    A bottle brush flex hone with take care of the cylinders. New OEM Suzuki rings and gaskets are best available. Viton valve stem seals are a worthwhile upgrade. That cam should run fine as long as there aren't any ugly marks on the running surfaces. Did you measure with a micrometer? Purchasing used cams will be a crapshoot with others worn just like yours.
    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


      #3
      Remeasured cam lobe height. Found it to be out of tolerance yet within service limits. No scoring on lobe surfaces. Should I keep them soaking in oil to prevent rust? Saw this in other vids.
      Another question...have access to 4 into 1 exhaust. Are there any advantages to be had. I still have the original 4 into 2 exhaust and I am tempted to trade out while I'm at it.

      Comment


        #4
        Can I do the valve stem upgrade or should I have it done by the shop that will clean up the head and valves?
        Also is there a good way to remove old gasket material?

        To measure is to know...excellent thought sir!
        Last edited by Guest; 07-10-2016, 02:05 PM. Reason: More questions

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          #5
          Getting off the old gasket material is by far the worst part of doing the entire rebuild. Only suggestion I can offer is to see if you can find the old type Permatex gasket remover. The new "low VOC" type sucks so stay clear. Dab it on with a brush, let it soak for 20 mins then scrape. You will have to do it several times before you get all the gasket off. Just take your time and drink lots of beer in between each step.

          You don't need to leave the cams soaking in oil. Just coat them and set them aside in a safe place. I've seen that video where the guy has his cams soaking in a bucket of oil and I laughed.

          You will need a valve spring compressor to break down the head but it's easy work. Steve made a video so try to find it. Mark each valve before you remove it and then clean and lap the valves before reassembly. If you can do the engine assembly work you can do the valves too. It's no big deal.
          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
            Found a new wrinkle...
            Measured pistons with a micrometer and found the pistons to be 72.75 mm so I now understand why I can see cross hatching in cylinders. Thanks again for your advice. John

            Comment


              #7
              Nothing to add except, if you want more power, Web Cams still makes performance cams for the GS1000.
              However, you only need more power in that bike if you, REALLY WANT MORE POWER.
              My stock 1100G has all the power I need.
              "Only fe' collected the old way, has any value." from His Majesty O'Keefe (1954 film)
              1982 GS1100G- road bike, body, seat and suspension modded
              1990 GSX750F-(1127cc '92 GSXR engine) track bike, much re-engineered
              1987 Honda CBR600F Hurricane; hooligan bike, restored

              Comment


                #8
                I don't think the shaft drive could handle much more. I could be wrong but I'm on a budget.
                Thanks for the tip. John

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