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    Camshaft wear.

    After having measured the camshafts on my GS1000EC, finding two (??) lobes undersized and after having two sets measured trying to find a replacement- only finding one camshaft of the two still above the service limits. After sending two camshafts to Ivor (psyguy) to replace the worn below service limits on his GS850GT and now finding one of the exhaust lobes on Stans (flyboy) GS1100GKE camshaft under spec, I've come to the conclusion that the camshafts on our bikes are either not properly ground or improperly heat treated.

    I've seen way to many undersized camshafts in just the small sample I've taken, for mine to be the only ones having this issue.

    Stan's exhaust camshaft 1-2-3-4
    1.3994 ~ 1.4075 ~ 1.3840 ~ 1.4080 (service limit 1.3965)


    Intake camshaft 1-2-3-4
    1.4265 ~ 1.4245 ~ 1.4285 ~ 1.4300 (service limit 1.4181)

    I calibrated my 1~2" mic on 12-22-2012 with one our service tech's 1" standard and double checked the lobe reading with my Mitutoyo dial calipers. Both instruments read exactly 1.3840"

    If you have your camshafts out for any reason may I suggest you measure yours for wear as well.
    Last edited by rustybronco; 12-29-2012, 06:16 PM.
    De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

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

    #2
    Originally posted by rustybronco View Post
    After having measured the camshafts on my GS1000EC, finding two (??) lobes undersized and after having two sets measured- only finding one camshaft still above the service limits. After sending two camshafts to Ivor (psyguy) to replace the worn below service limits on his GS850GT and now finding one of the exhaust lobes on Stans (flyboy) GS1100GKE camshaft, I've come to the conclusion that the camshafts on our bikes are either not properly ground or improperly heat treated.

    I've seen way to many undersized camshafts in just the small sample I've taken for mine to be the only ones having this issue.

    Stan's exhaust camshaft 1-2-3-4
    1.3994 ~ 1.4075 ~ 1.3840 ~ 1.4080 (service limit 1.3965)


    Intake camshaft 1-2-3-4
    1.4265 ~ 1.4245 ~ 1.4285 ~ 1.4300 (service limit 1.4181)

    I calibrated my 1~2" mic on 12-22-2012 with one our service tech's 1" standard and double checked the lobe reading with my Mitutoyo dial calipers. Both instruments read exactly 1.3840"

    If you have your camshafts out for any reason may I suggest you measure yours for wear as well.
    Yep they wear and you are well advised to measure them when evaluating any cams. Don't just look for visual indications of wear.

    Comment


      #3
      Originally posted by posplayr View Post
      Yep they wear and you are well advised to measure them when evaluating any cams. Don't just look for visual indications of wear.
      No Jim, you can't tell by looking at them. But why am I seeing I seen so many bad ones?? that's what I can't understand. And it's not like the most wear is found on number four camshaft lobe either.
      De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

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

      Comment


        #4
        Originally posted by rustybronco View Post
        No Jim, you can't tell by looking at them. But why am I seeing I seen so many bad ones?? that's what I can't understand. And it's not like the most wear is found on number four camshaft lobe either.
        Yes as Ed says "To Measure is to Know", we are saying the same thing.

        Comment


          #5
          Jim
          Measure those 1150 cams and post the results.
          1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
          1985 GS1150ES stock with 85 Red E bodywork.

          Comment


            #6
            I've also seen worn cams before. Surprising considering how durable the shim and bucket engines are. The valve pockets hold a puddle of oil which assures the lobes get plenty of lube. My guess is the metal is a little soft. At any rate, good thing is the 750, 850 1000 and 1100G cams all interchange. Not sure about the cam drive sprockets but suspect they interchange too.
            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


              #7
              Ed, it's very surprising indeed and I never would have expected it either.
              De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

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

              Comment


                #8
                The 750 is a different cam, it fits but he lift and duration is different, for more high revving fun.
                http://img.photobucket.com/albums/v5...tatesMap-1.jpg

                Life is too short to ride an L.

                Comment


                  #9
                  Originally posted by tkent02 View Post
                  The 750 is a different cam, it fits but he lift and duration is different, for more high revving fun.
                  So if the 750 cams are used in a 1000 will there be a noticable power difference ?I have many sets of 750 cams and a couple 1000"S
                  1984 GS1100GK newest addition to the heard
                  80 GS 1000gt- most favorite ride love this bike
                  1978 GS1000E- Known as "RoadKill" , Finished :D
                  83 gs750ed- first new purchase
                  85 EX500- vintage track weapon
                  1958Ducati 98 Tourismo
                  “Remember When in doubt use full throttle, It may not improve the situation ,but it will end the suspense ,
                  If it isn't going to make it faster or safer it isn't worth doing

                  Comment


                    #10
                    The timing difference between the 750 and 1000 is only a few degrees. Not enough to matter. Lift is slightly lower lift too, although again, it's not enough to matter.
                    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


                      #11
                      Originally posted by hjfisk View Post
                      So if the 750 cams are used in a 1000 will there be a noticable power difference ?I have many sets of 750 cams and a couple 1000"S
                      Try it and see, it used to be one of the things people did to wake up a 1000.
                      If you have the cams sitting around, take an hour or two and throw a set in.
                      I have not done it myself so I can't say for sure, but the two engines are definitely different in their power delivery, the 750 has less low end grunt and comes on harder at a higher RPM.

                      The 750 and 850 feel much different as well, the two engines are identical except cylinder bore and cams. Same head and everything, but the 850 shares the more sedate 1000 cam.
                      http://img.photobucket.com/albums/v5...tatesMap-1.jpg

                      Life is too short to ride an L.

                      Comment


                        #12
                        Originally posted by tkent02 View Post
                        Try it and see, it used to be one of the things people did to wake up a 1000.
                        If you have the cams sitting around, take an hour or two and throw a set in.
                        I have not done it myself so I can't say for sure, but the two engines are definitely different in their power delivery, the 750 has less low end grunt and comes on harder at a higher RPM.

                        The 750 and 850 feel much different as well, the two engines are identical except cylinder bore and cams. Same head and everything, but the 850 shares the more sedate 1000 cam.
                        So the 850 uses the same head as the 750? this is good info. I may try that cam switch on 1 of the 1000's this winter , as I have to tear it down to do the head gasket anyway.
                        1984 GS1100GK newest addition to the heard
                        80 GS 1000gt- most favorite ride love this bike
                        1978 GS1000E- Known as "RoadKill" , Finished :D
                        83 gs750ed- first new purchase
                        85 EX500- vintage track weapon
                        1958Ducati 98 Tourismo
                        “Remember When in doubt use full throttle, It may not improve the situation ,but it will end the suspense ,
                        If it isn't going to make it faster or safer it isn't worth doing

                        Comment


                          #13
                          Originally posted by hjfisk View Post
                          So the 850 uses the same head as the 750? this is good info. I may try that cam switch on 1 of the 1000's this winter , as I have to tear it down to do the head gasket anyway.
                          The 1979 850 used the same head as the 1977 - 1979 750, identical part number and everything.

                          In 1980 on the 850 they went to the CV carbs, so the intake ports are bigger to fit them. In every other way the head is identical to the 1979 head.

                          In 1980 they went with the 16 valve head for the 750, it is an an entirely different engine.
                          http://img.photobucket.com/albums/v5...tatesMap-1.jpg

                          Life is too short to ride an L.

                          Comment


                            #14
                            Originally posted by tkent02 View Post
                            The 1979 850 used the same head as the 1977 - 1979 750, identical part number and everything.

                            In 1980 on the 850 they went to the CV carbs, so the intake ports are bigger to fit them. In every other way the head is identical to the 1979 head.

                            In 1980 they went with the 16 valve head for the 750, it is an an entirely different engine.
                            Yes I knew about the 80 750 being a 16 valve but I did not know that the earlier 750/850's shared the same head just different cams.
                            1984 GS1100GK newest addition to the heard
                            80 GS 1000gt- most favorite ride love this bike
                            1978 GS1000E- Known as "RoadKill" , Finished :D
                            83 gs750ed- first new purchase
                            85 EX500- vintage track weapon
                            1958Ducati 98 Tourismo
                            “Remember When in doubt use full throttle, It may not improve the situation ,but it will end the suspense ,
                            If it isn't going to make it faster or safer it isn't worth doing

                            Comment

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