Low Compression

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  • little wagon

    #16
    Looks like I will be setting the valves then, on the wet compression test can I put in hydraulic valve lifter treatment in the cylinder to loosen the rings or just stick with oil
    Will be sorting the points once I fix the Black and White wire as it has about 10 breaks in it, rock hard and the White end to points has come off!
    More joy lol

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    • Nessism
      Forum LongTimer
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      • Mar 2006
      • 35791
      • Torrance, CA

      #17
      I'd put gunked up carbs as the number one reason bikes hit long term storage, but the valves are probably the number one reason they hit the scrap heap (or become bobber/cafe fodder).
      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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      • tkent02
        Forum LongTimer
        Past Site Supporter
        • Jan 2006
        • 35571
        • Near South Park

        #18
        Originally posted by Nessism
        I'd put gunked up carbs as the number one reason bikes hit long term storage, but the valves are probably the number one reason they hit the scrap heap (or become bobber/cafe fodder).

        Originally posted by little wagon
        Will be sorting the points once I fix the Black and White wire as it has about 10 breaks in it, rock hard and the White end to points has come off!
        More joy lol
        Broken ignition wires is likely another valid reason, although it's a new one on me.
        http://img.photobucket.com/albums/v5...tatesMap-1.jpg

        Life is too short to ride an L.

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        • bwringer
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          • 17066
          • Indianapolis

          #19
          Let's not forget lost titles. Missing papers are probably the #1 killer of neat old bikes in states where obtaining a replacement title is impossible or nearly impossible.
          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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          • little wagon

            #20
            Did a wet compression test today
            Dry results: Were 1: 75psi 2: 55 psi 3: 65 psi 4: 53 psi
            Wet results: Are 1: 82 psi 2: 62 psi 3: 80 psi 4: 65 psi
            Not sure how much extra psi they are supposed to go up by? But seems a bit better

            Little Wagon

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            • Nessism
              Forum LongTimer
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              • Mar 2006
              • 35791
              • Torrance, CA

              #21
              Originally posted by little wagon
              Did a wet compression test today
              Dry results: Were 1: 75psi 2: 55 psi 3: 65 psi 4: 53 psi
              Wet results: Are 1: 82 psi 2: 62 psi 3: 80 psi 4: 65 psi
              Not sure how much extra psi they are supposed to go up by? But seems a bit better

              Little Wagon
              The fact that the compression didn't increase with the oil suggests the valves are leaking. How did that valve adjustment check go?

              Also, as already mentioned, performing a compression test on an engine that hasn't run in 20 years is inconclusive anyway.
              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

              • little wagon

                #22
                Not got around to valve adjustment as of yet, managed to sort the starter solenoid out so the engine turns over every time I press the starter button
                Would like to get spark next, but the old saying comes in to play, all work and no time to do bike!
                Good job it is a long term project lol

                Comment

                • Nessism
                  Forum LongTimer
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                  • 35791
                  • Torrance, CA

                  #23
                  Originally posted by little wagon
                  Not got around to valve adjustment as of yet, managed to sort the starter solenoid out so the engine turns over every time I press the starter button
                  Would like to get spark next, but the old saying comes in to play, all work and no time to do bike!
                  Good job it is a long term project lol
                  So everyone told you to adjust the valves and you ignored us.
                  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

                  • little wagon

                    #24
                    You know lol
                    Bit wary with doing the valves, do some of the things I can do first and build up the confidence
                    Last time I did the valves on a Honda Super dream I managed to drop a valve (Oh dear)

                    Comment

                    • JRHemmen

                      #25
                      I've got a GS450 that had some pretty awful compression numbers until I did a valve adjustment and lapping. I had never worked inside an engine before, and I was pleasantly surprised by how easy valve adjustment is. Pick up the Suzuki Valve bucket compressor tool at http://www.amazon.com/Motion-Pro-08-.../dp/B000UKIN8Q and rent a valve spring compressor from your local auto parts store. If you manage to get your hands on a valve spring compressor meant for motorcycles/small engines, it won't take any time at all. BaltimoreGS has a series on Youtube where she rebuilds a GS500 engine, I'll link the segment where she goes over the cylinder head. Its a 4 part segment, even though you have a 4 cylinder I'd recommend watching the series, it was really helpful, to me anyway. Good luck and let us know how it goes!

                      GS500 Top End Rebuild (Part 2 of 4)

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                      • tkent02
                        Forum LongTimer
                        Past Site Supporter
                        • Jan 2006
                        • 35571
                        • Near South Park

                        #26
                        Just adjusting the valves will probably work wonders. There can't be much compression if the valves are not closing.
                        http://img.photobucket.com/albums/v5...tatesMap-1.jpg

                        Life is too short to ride an L.

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                        • tkent02
                          Forum LongTimer
                          Past Site Supporter
                          • Jan 2006
                          • 35571
                          • Near South Park

                          #27
                          Or just run it and burn them all up.
                          http://img.photobucket.com/albums/v5...tatesMap-1.jpg

                          Life is too short to ride an L.

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                          • JRHemmen

                            #28
                            I should probably add that I had bad compression even after changing shims. Lapping the valves is what worked wonders for me. I swapped my valves to a new head though so it may be different in your case.

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