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    #1

    Cylinder Diameters

    Ok, so I've had low compression in my cylinders, and when I added oil to the cylinders then the compression skyrocketed into spec, so I took my top end apart and this is what I found.
    Cylinder 1:

    Cylinder 2:

    All others look like 1. I guess I'm safe to assume I need new pistons. The bore that pistons corresponds to looks like this:

    I got out the bore gage and these are the measurements.

    Cylinder 1:
    Top
    Vertical 2.7178
    Horizontal 2.7172

    Middle
    Vertical 2.7181
    Horizontal 2.7179

    Bottom
    Vertical 2.7181
    Horizontal 2.7182

    Cylinder 2:
    Top
    Vertical 2.7180
    Horizontal 2.7174

    Middle
    Vertical 2.7184
    Horizontal 2.7175

    Bottom
    Vertical 2.7183
    Horizontal 2.7175

    Cylinder 3:
    Top
    Vertical 2.7176
    Horizontal 2.7178

    Middle
    Vertical 2.7181
    Horizontal 2.7178

    Bottom
    Vertical 2.7184
    Horizontal 2.7177

    Cylinder 4:
    Top
    Vertical 2.7180
    Horizontal 2.7173

    Middle
    Vertical 2.7177
    Horizontal 2.7178

    Bottom
    Vertical 2.7179
    Horizontal 2.7181

    Do these look okay? From what I understand I can just hone the cylinders, buy new pistons and rings, put it back together and seat the rings. Can someone who knows more about these bore specs confirm this for me?
    Tags: None
    #2
    Going to have to convert all those inch measurements to metric, so they make sense to everyone here.

    Just a hint, for those that might know the sizes, 2.718 inches is 69.0372 mm.

    .
    [SIGPIC][/SIGPIC]
    mine: [URL="http://tinyurl.com/btyzw4z"]2000 Honda GoldWing GL1500SE [/URL]and [URL="http://tinyurl.com/o6vqacs"]1980 GS850G'K'[/URL] "Junior"
    hers: [URL="https://tinyurl.com/yaapydtv"]1982 GS850GL[/URL] - [URL="http://tinyurl.com/cospp3s"]"Angel" [/URL]and [URL="http://tinyurl.com/bqnpjx9"]1969 Suzuki T250 Scrambler [/URL]
    #1 son: [URL="http://tinyurl.com/d7c8duu"]1986 Yamaha Venture Royale 1300 [/URL]and [URL="http://tinyurl.com/ou7k3lp"]1982 GS650GL[/URL] "Rat Bagger"
    #2 son: 1[URL="http://tinyurl.com/buxhls6"]980 GS1000G [/URL]
    [URL="http://tinyurl.com/d4ojmal"]Family Portrait [/URL]
    [URL="http://tinyurl.com/cbo3ojk"]Siblings and Spouses[/URL]
    [URL="http://tinyurl.com/ctr8k54"]Mom's first ride[/URL]
    [B]Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM) [/B]
    [SIZE=1](Click on my username in the upper-left corner for e-mail info.)[/SIZE]

    Comment

      #3
      Conversion is as follows:

      Cylinder 1:
      Top
      Vertical 69.032
      Horizontal 69.017

      Middle
      Vertical 69.040
      Horizontal 69.035

      Bottom
      Vertical 69.040
      Horizontal 69.042

      Cylinder 2:
      Top
      Vertical 69.037
      Horizontal 69.022

      Middle
      Vertical 69.047
      Horizontal 69.025

      Bottom
      Vertical 69.045
      Horizontal 69.025

      Cylinder 3:
      Top
      Vertical 69.027
      Horizontal 69.032

      Middle
      Vertical 69.040
      Horizontal 69.032

      Bottom
      Vertical 69.047
      Horizontal 69.030

      Cylinder 4:
      Top
      Vertical 69.037
      Horizontal 69.019

      Middle
      Vertical 69.030
      Horizontal 69.032

      Bottom
      Vertical 69.035
      Horizontal 69.040

      Comment

        #4
        Compare the numbers to those in the service manual.

        That one cylinder seized. You need to replace the liner or bore that cylinder oversize.
        Ed

        To measure is to know.

        Mikuni O-ring Kits For Sale...[url]https://www.thegsresources.com/_forum/forum/consumer-information/gs-parts-and-services/1703182-mikuni-bs-cv-and-vm-o-ring-kits#post1703182[/url]

        Top Newbie Mistakes thread...[URL="http://www.thegsresources.com/_forum/showthread.php?t=171846"]http://www.thegsresources.com/_forum...d.php?t=171846[/URL]

        Carb rebuild tutorial...[URL="https://gsarchive.bwringer.com/mtsac/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf"]https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf[/URL]

        KZ750E Rebuild Thread...[URL="http://www.thegsresources.com/_forum/showthread.php?217199-1981-Kawasaki-KZ750-Resurrection"]http://www.thegsresources.com/_forum...0-Resurrection[/URL]

        Comment

          #5
          They're all inside the service limit. They're outside the standard specs. Aren't the standard specs intended for the machinists though? Also, I couldn't find a spec for out of round or taper in the service manual unless it's cylinder head distortion which is .2mm which sounds like a lot.

          Comment

            #6
            You also need to determine why this happened to #2. This type of damage doesn't just happen, there is a reason. Probably running lean, since #2 is the carb which supplies vacuum to the petcock a leaking vacuum line is likely the culprit. Could be a bad intake boot or something else causing it to run lean.
            If you don't find the problem your brand new #2 piston will look about the same as this one (or worse) before too long.
            [IMG]http://img.photobucket.com/albums/v516/Tkent02/VisitedStatesMap-1.jpg[/IMG]

            Life is too short to ride an L.

            Comment

              #7
              My understanding is that you don't want more than about .001" out of round or taper in any given hole. The Piston to cylinder clearance should also be determined and can't exceed the service limit. Again though, your number 2 cylinder is going to be scored all to crap, and bottle brush honing won't clean that up. Your best bet may be to find a new-used cylinder from a low mileage engine.
              Ed

              To measure is to know.

              Mikuni O-ring Kits For Sale...[url]https://www.thegsresources.com/_forum/forum/consumer-information/gs-parts-and-services/1703182-mikuni-bs-cv-and-vm-o-ring-kits#post1703182[/url]

              Top Newbie Mistakes thread...[URL="http://www.thegsresources.com/_forum/showthread.php?t=171846"]http://www.thegsresources.com/_forum...d.php?t=171846[/URL]

              Carb rebuild tutorial...[URL="https://gsarchive.bwringer.com/mtsac/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf"]https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf[/URL]

              KZ750E Rebuild Thread...[URL="http://www.thegsresources.com/_forum/showthread.php?217199-1981-Kawasaki-KZ750-Resurrection"]http://www.thegsresources.com/_forum...0-Resurrection[/URL]

              Comment

                #8
                Originally posted by tkent02 View Post
                You also need to determine why this happened to #2. This type of damage doesn't just happen, there is a reason. Probably running lean, since #2 is the carb which supplies vacuum to the petcock a leaking vacuum line is likely the culprit. Could be a bad intake boot or something else causing it to run lean.
                If you don't find the problem your brand new #2 piston will look about the same as this one (or worse) before too long.
                Sorry I forgot about that part. You're dead on with what caused this. The #2 carb boot was coming apart so the mixture had been really lean. I've got a new set I'll put on before I put it all together.

                Originally posted by Nessism View Post
                My understanding is that you don't want more than about .001" out of round or taper in any given hole. The Piston to cylinder clearance should also be determined and can't exceed the service limit. Again though, your number 2 cylinder is going to be scored all to crap, and bottle brush honing won't clean that up. Your best bet may be to find a new-used cylinder from a low mileage engine.
                At the worst spots the cylinder is .0009 out. I've got a nice professional hone at work, so I'll see how well it can clean up the scoring. If that doesn't work then I'll get on eBay and pick me up a used set of cylinders.

                As always, thanks for the help guys.

                Comment

                  #9
                  K, after copius amounts of homing cylinder 2 looks like this.

                  It's time for a new cylinder or boring, right?

                  Comment

                    #10
                    This is for an 850?? If it is I have your cylinders.
                    [IMG]http://img.photobucket.com/albums/v516/Tkent02/VisitedStatesMap-1.jpg[/IMG]

                    Life is too short to ride an L.

                    Comment

                      #11
                      If you want just one liner, I have a block with just three liners in it, no problem to remove another one.

                      Cheaper to ship just one liner, too.

                      .
                      [SIGPIC][/SIGPIC]
                      mine: [URL="http://tinyurl.com/btyzw4z"]2000 Honda GoldWing GL1500SE [/URL]and [URL="http://tinyurl.com/o6vqacs"]1980 GS850G'K'[/URL] "Junior"
                      hers: [URL="https://tinyurl.com/yaapydtv"]1982 GS850GL[/URL] - [URL="http://tinyurl.com/cospp3s"]"Angel" [/URL]and [URL="http://tinyurl.com/bqnpjx9"]1969 Suzuki T250 Scrambler [/URL]
                      #1 son: [URL="http://tinyurl.com/d7c8duu"]1986 Yamaha Venture Royale 1300 [/URL]and [URL="http://tinyurl.com/ou7k3lp"]1982 GS650GL[/URL] "Rat Bagger"
                      #2 son: 1[URL="http://tinyurl.com/buxhls6"]980 GS1000G [/URL]
                      [URL="http://tinyurl.com/d4ojmal"]Family Portrait [/URL]
                      [URL="http://tinyurl.com/cbo3ojk"]Siblings and Spouses[/URL]
                      [URL="http://tinyurl.com/ctr8k54"]Mom's first ride[/URL]
                      [B]Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM) [/B]
                      [SIZE=1](Click on my username in the upper-left corner for e-mail info.)[/SIZE]

                      Comment

                        #12
                        Originally posted by tkent02 View Post
                        This is for an 850?? If it is I have your cylinders.
                        Originally posted by Steve View Post
                        If you want just one liner, I have a block with just three liners in it, no problem to remove another one.

                        Cheaper to ship just one liner, too.

                        .
                        Sorry, had I seen this earlier I'd take you up on it. I ordered some off ebay. If they end up not working out I'll buy them from one of you two.

                        Comment

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