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'78 GS750 EC engine rebuild. Necessary to remove the rotor?

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    '78 GS750 EC engine rebuild. Necessary to remove the rotor?

    I'm fully tearing down my GS750 engine so I can more fully clean and rebuild everything. I'm not really planning on doing anything to the crank other than taking it out and once everything is clean reinstalling it. Do I need to remove the rotor?

    I've tried everything I can think of to try to get it off but the thing won't budge. My rotor has 14mmx1.5 internal threads and then a 12mm (i think) bolt that goes through the center into the crank. I've tried a slide hammer which involved me making a 14mm adapter. This didn't work even with some heat. I also ordered and received a Bike Master 14mmx1.5 remover today and I managed to get it on there so tight it started to crush the 14mm bolt into the 12mm threads inside the crank. It also bent the remover.

    So basically if I split the cases and leave the rotor on am I going to have any problems?

    Thanks in advance. I want to keep moving on this rebuild but this rotor has been an issue for the past week or so.

    #2
    Come on guys - I'm waiting for an answer on this one too. It's behind the stator, the starter clutch gear, right?

    According to the Suzuki manual it should slide off after removal of the bolt.
    Last edited by allojohn; 09-02-2012, 09:44 PM. Reason: added info
    -Mal

    "The only reason for time is so that everything doesn't happen at once." - B. Banzai
    ___________

    78 GS750E

    Comment


      #3
      u need a puller it doesn not just slide off as far as i know,the starter clutch and whatnot on the left side u need a puller.on the right side the rotor i belive slides off after removing the bolt and points or pickup module depending on year or mods.

      Comment


        #4
        If the GS is truly a copy of the KZ engine, no. I completely rebuilt my GPz (which is a souped up KZ engine) with the rotor still attached.

        Comment


          #5
          1. No, you don't need to remove the rotor
          2. But, it's a good idea, so you can check the starter clutch bolts (common issue)
          1978 GS 1000 (since new)
          1979 GS 1000 (The Fridge, superbike replica project)
          1978 GS 1000 (parts)
          1981 GS 850 (anyone want a project?)
          1981 GPZ 550 (backroad screamer)
          1970 450 Mk IIID (THUMP!)
          2007 DRz 400S
          1999 ATK 490ES
          1994 DR 350SES

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            #6
            Pretty sure it's the same for all the GS's that you can screw in the rear axle (or appropriate sized bolt) on top of a spacer and give it a tap with a hammer to pop it off??

            That was how it said to do it in the 450 manual, anyways.
            Current:
            Z1300A5 Locomotive (swapped my Intruder for it), GS450 Cafe Project (might never finish it....), XT500 Commuter (I know - it's a Yamaha :eek:)

            Past:
            VL1500 Intruder (swapped for Z1300), ZX9R Streetfighter (lets face it - too fast....), 1984 GSX750EF, 1984 GSX1100EF (AKA GS1150)
            And a bunch of other crap Yamahas....

            Comment


              #7
              OK. I'm going to proceed with the rotor on. I've tried every method mentioned on these forums and in three different manuals without luck getting the rotor off.

              The bike is going to be kick only do the starter clutch bolts that Big T mentioned aren't a concern.

              I'll start taking better quality photos do I can start a build thread.

              Thanks, guys.
              Last edited by Guest; 09-03-2012, 09:48 AM. Reason: Premature posting

              Comment


                #8
                Big T got it right...just get a bolt the same thread as the one in the center of the rotor about 4 or 5 inches long and thread it in till it snugs up. Then with the box end of the wrench on the bolt, give it a quick smack with the hammer and the rotor will pop right off. remove the bolts from the starter clutch and look for any evidence of wear on them from any slippage of the clutch. Clean everything well with some parts cleaner spray and blow dry with an air hose. rebolt it back to the rotor and use RED locktite. YES THEY ARE A CONCERN!!!!!!!!!!!!! If they come loose and the clutch flys off its gonna tear the flywheel and possibly crank end all to crap and possibly break a hole in the engine case if it goes real bad. You either fix it right or remove it all together...no shortcuts i am afraid!!!
                Last edited by chuck hahn; 09-03-2012, 10:57 AM.
                MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                Comment


                  #9
                  AND...even if it just comes loose, youll get the god awfullest clatter and vibrations that will have you redoing it all anyways...so bite the bullet and get it either rebolted or remove the flywheel and clutch all together. Dont toss them though...some day you may want to go back to electric start or sell the bike and the oarts will be of great value down the road.
                  MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                  1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                  NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                  I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                  Comment


                    #10
                    The thing won't come off. I've tried a bolt, the rotor remover, and a slide hammer. I even tried an impact driver on the rotor tool. No dice. The thing is on there and does not want to move.

                    Could anything else be holding it on? I've removed rotors from plenty of bikes but I have never run into one this stuck.

                    Comment


                      #11
                      Put the bolt in and tighten the dog snot out of it.. short of stripping it out...then use a dead blow hammer and give the rotor some good old fashioned thumps. They are sometimes a real pain in the azz but nthey will come off. Thats the only way to remove the clutch and the flywheel to make it the way you want .
                      MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                      1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                      NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                      I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                      Comment


                        #12
                        They just sometimes fused and are impossible to get off. At one shop, we had the correct puller and a super duty 1/2" impact, while prying from behind, and it would not budge. Had to cut that one off, NO FUN! If you continue hammering on the rotor, you may demagnetize or shatter the magnets, so it's best to stop now. If your starter clutch bolts come loose later, then deal with it.

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