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    Top End Rebuild

    I think I traced a disturbing noise to a valve issue, so since I've wanted to rebuild the top end for a while, I'm going for it, hoping to find the valve issue in the process.

    Looking for feedback on parts/tools list, if any, thanks! This is already going to be more expensive than I imagined at first. Head gasket and 4 x cylinder ring sets quickly get you over $200 without all the rest of the sundries.

    But the hope is... 1.) Fix my tapping noise 2.) basically have a rebuilt engine that'll go another 10 years of daily driving.

    EDIT: I'm not sure the exact mileage, as my odometer stopped working years ago, but I'd estimate at close to 75K. 4-5 years of 20-30 minute week-daily commutes + other riding after the clock stopped at 43K.

    Starting with parts list, mainly for my own notes...

    Parts:

    Head Gasket - 11141-49410
    Rectangular Oring - 09280-99003
    Valve Oil Seal (1 per valve) - 11141-49410
    Valve spring set (1 per Valve - as needed) - 12920-45011
    "Cotter, Valve" (this is what the valve spring compressor releases - not sure if they need to be replaced as a plan or only as needed) - 12932-45010

    Base Gasket - 11241-45110-H17
    Big cylinder oring - 09280-70001
    Littler oring - 09280-21004

    Piston Ring set (1 per piston) - 12140-49001
    Piston Pin Circlip (As needed?) - 09381-16001

    Tools I don't already own:
    Valve spring compressor
    Valve lapping tool
    Big vice grip or similar to hold down cams
    2 3/4" (69.85mm) Flex ball hone
    Last edited by Guest; 05-20-2014, 11:05 AM.

    #2
    Some of what you want or need to do will depend on what you find inside once it's apart. Also how many miles engine has on it. You may not need to replace valve springs, just measure them with digital caliper and make sure they still in spec. (get a manual off Basscliff's site if you don't have one, will list all these specs.) May not need new piston rings if still within specs. Valve lapping tool is about $6-7 at any auto parts store and valve grinding compound is not much more. Do want to replace valve seals. I would buy all the gaskets and O-rings then tear it apart before ordering much more. Check everything out and measure everything you should, unless you can afford it, then go head with plans. Will need to lightly hone piston cylinder, check ebay for honing ball, or see if someone on here could loan you one. Have to replace piston circlips. I'm no expert, these are things I was told before I did mine recently. Others will come along with more advise. terrylee

    Comment


      #3
      Piston Ring set (1 per piston) - 12140-49001

      Just check the part number for the rings. Your number is for the 1mm oversize rings for the 850. The standard size rings for the 850 are part number 12140-45120. I ordered the wrong size once and will never make same mistake again. Hope this helps. Regards
      GED

      1980 GS850G (BLACK)
      http://www.thegsresources.com/_forum...d.php?t=185562
      1980 GS850G (RED) http://www.thegsresources.com/_forum...d.php?t=219169
      1980 GS850G (SILVER) (Coming soon)

      There are old riders and there are bold riders but there are no old bold riders!!!!!!


      Comment


        #4
        Confusion comes from the fact that the 1mm oversized ring for the 850 is the standard ring for the 1000. Took months to get the right 850 rings for my 750/850 engine, in the end I put a 1000 engine in the 750 because it was so much quicker than waiting for the rings.

        And don't buy anything from RideNow, they are completely incompetent and still owe me money.
        http://img.photobucket.com/albums/v5...tatesMap-1.jpg

        Life is too short to ride an L.

        Comment


          #5
          Originally posted by Roostabunny View Post

          Tools I don't already own:
          Valve spring compressor
          Valve lapping tool
          Big vice grip or similar to hold down cams
          Don't need.
          Don't need.
          Don't need.


          Your fingers work just as well.
          Loosen the cam cap covers evenly. Tighten the same way. One turn at a time.
          De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

          http://www.thegsresources.com/_forum...35#post1625535

          Comment


            #6
            Originally posted by terrylee View Post
            Some of what you want or need to do will depend on what you find inside once it's apart. Also how many miles engine has on it. You may not need to replace valve springs, just measure them with digital caliper and make sure they still in spec. (get a manual off Basscliff's site if you don't have one, will list all these specs.) May not need new piston rings if still within specs. Valve lapping tool is about $6-7 at any auto parts store and valve grinding compound is not much more. Do want to replace valve seals. I would buy all the gaskets and O-rings then tear it apart before ordering much more. Check everything out and measure everything you should, unless you can afford it, then go head with plans. Will need to lightly hone piston cylinder, check ebay for honing ball, or see if someone on here could loan you one. Have to replace piston circlips. I'm no expert, these are things I was told before I did mine recently. Others will come along with more advise. terrylee
            Very good! I do have the manual and digital caliper. Valve lapping tools/materials are cheap, and as Rustybronco mentioned, the tool (aka suction cup on a stick, I think) is not 100% necessary. I put the spring part# on there mainly because i suspect I have at least one that's failed, but yes, that's a "wait and see" part.

            I'll look around for ball hones. I'd love to borrow one, for how often it'll get used, but shipping two ways might end up being close to the purchase price, so I'll figure that out. Any feedback on the 2-3/4" size for an 850?

            Comment


              #7
              Originally posted by ged View Post
              Piston Ring set (1 per piston) - 12140-49001

              Just check the part number for the rings. Your number is for the 1mm oversize rings for the 850. The standard size rings for the 850 are part number 12140-45120. I ordered the wrong size once and will never make same mistake again. Hope this helps. Regards
              Oh, Nice catch! I see it now in the description ... "PISTON RING SET (OS:1.0)"

              I got this one:
              PISTON RING SET (STD)
              12140-45121


              Which is (I think) the replacement part# for the ...120 one you put in.

              Comment


                #8
                The GS850 and 1000 share the same head gasket. You may want to look at ebay for a good price on an OEM head gasket, and other gaskets as well. Viton valve stem seals from ebay have received good reviews by some members here too (rapid ray uses them).

                Regarding the square O-ring around the cam chain tunnel, the later design head gaskets don't use this part so keep this in mind.

                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 tkent02 View Post
                  Confusion comes from the fact that the 1mm oversized ring for the 850 is the standard ring for the 1000. Took months to get the right 850 rings for my 750/850 engine, in the end I put a 1000 engine in the 750 because it was so much quicker than waiting for the rings.

                  And don't buy anything from RideNow, they are completely incompetent and still owe me money.
                  Yeah, I'm thankful for ged catching that.

                  I've never used Ridenow, but after several mediocre experiences with BikeBandit I'm a little leary of any of the big parts houses in the clouds.

                  I've inquired with Z1 for pricing on these OEM gaskets and oil seals, we'll see what they come back with.

                  Comment


                    #10
                    Originally posted by Nessism View Post
                    The GS850 and 1000 share the same head gasket. You may want to look at ebay for a good price on an OEM head gasket, and other gaskets as well. Viton valve stem seals from ebay have received good reviews by some members here too (rapid ray uses them).

                    Regarding the square O-ring around the cam chain tunnel, the later design head gaskets don't use this part so keep this in mind.

                    http://www.ebay.com/itm/1978-1979-Su...9c3823&vxp=mtr
                    Wow, that's a good tip for potential money savings!

                    I'm curious about the different head gasket designs. Are you saying that some gaskets incorporate or don't need that separate o-ring?

                    Comment


                      #11
                      Originally posted by Roostabunny View Post
                      Wow, that's a good tip for potential money savings!

                      I'm curious about the different head gasket designs. Are you saying that some gaskets incorporate or don't need that separate o-ring?
                      The MLS type gaskets don't use the square O-ring. Not sure about the full history though.
                      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


                        #12
                        Originally posted by rustybronco View Post
                        Don't need.
                        Don't need.
                        Don't need.


                        Your fingers work just as well.
                        Loosen the cam cap covers evenly. Tighten the same way. One turn at a time.
                        Yeah, ha - one of the things I googled after this post was "DIY valve spring tools".

                        Valve spring tool: I've seen the chopped socket designs as well as come interesting drilled pipe types - how'd you attach the socket?

                        Lapping tool: So noted. I have read quite a bit about the potential for overlapping the valves, and I could see how the tool would encourage that. People going all boy-scout-starting-a-campfire on their valves.

                        Vice-grip/Camshaft holder-downer: I think you're saying the point is to NOT allow racking/twisting force on the journals, but caution/patience works as well as a tool?

                        Comment


                          #13
                          Originally posted by Nessism View Post
                          The MLS type gaskets don't use the square O-ring.
                          I'm racking my brain here.

                          Wait, I'll get it...

                          Multiple Layer Subtractor?
                          Metallic Leverage Substance?
                          Martian Landmass Syncopator?

                          EDIT - Google to the rescue, sorry. MLS = Multi-layer Steel. I actually came close.
                          Last edited by Guest; 05-20-2014, 10:53 AM.

                          Comment


                            #14
                            FWIW - I added this in the original post, but for those who've already read this far...

                            I'm not sure the exact mileage on the bike, as my odometer stopped working years ago, but I'd estimate at close to 75K. 4-5 years of 20-30 minute week-daily commutes + other riding after the clock stopped at 43K.

                            Anyway, not low miles, but fairly well cared for. Just a data point, I'll still measure against the specs.
                            Last edited by Guest; 05-20-2014, 11:10 AM.

                            Comment


                              #15
                              The correct tool for the job, and one that doesn't allow parts to fly all over the shop and get lost, really does not cost much at all and can be used on other projects including your lawn mower/tractor, 4-and 6 cylinder car/truck, etc.

                              Or, you can waste time/money doing other silly stuff like making a tool out of PCV pipe/modified socket, using zip ties instead of the factory valve shim tool (under $20) and breaking bolts by NOT using a clicker type torque wrench.
                              The choice is yours.

                              Comment

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