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Anyone ever have your brake rotors ground?

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    Anyone ever have your brake rotors ground?

    I've got .005" run-out on one of my rotors which is in spec, but I was able to feel a pulsing in the brake lever on a different bike with this much warpage.

    Has anyone ever had a rotor ground and if so how much did you pay? There is a guy on ebay that wants $45 each rotor, plus there would be transit costs too. I'll do it if it's worth doing.
    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

    #2
    I never have, but I don't see why they can't be cut just like any other rotor.
    Set-up would be a bit different, but should work the same.

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      #3
      I seem to remember the ebay guy being well thought of around here. You can't cut these rotors like a normal rotor, since they're steel. You need to blanchard, or surface grind them, in order to do the job correctly. New rotors are something close to $250 or so? $45 seems pretty decent, if it's done properly. Figure $15 bucks shipping each way.

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        #4
        Depends on how much meat is left on the rotor...if it's close to the lower limit, it's a waste of money truing them for maybe a one year lifespan after grinding. There are plenty of rotors that come up on ebay etc. as the same rotors were used on many different models. Look for thickness specs before bidding (to measure is to know), but it's still a crap shoot WRT trueness....odds are, if you get cosmetically good low-mile rotors, they should be true .
        '82 GS1100E



        Originally posted by themess
        Only in your own mind did you refute what I wrote.

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          #5
          I had my single rotor GS reground years ago - it was about $30 back then, so $45 shoulkd be good.


          I don't know why you couldn't find a machine shop nearby that does this work. You're in LA, not the sticks of ND
          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

          Comment


            #6
            u know if u torque the bolts all the same the warpage will decress over time. they warp cuz the bolt torque isnt the same on all the bolts. when it heats up there are different pressures on the rotor by the bolts being tight or loose. try that first thats what i did took about 3K to notice it but it was cheaper

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              #7
              Originally posted by crazypaint View Post
              u know if u torque the bolts all the same the warpage will decress over time. they warp cuz the bolt torque isnt the same on all the bolts. when it heats up there are different pressures on the rotor by the bolts being tight or loose. try that first thats what i did took about 3K to notice it but it was cheaper
              I don't see how bolt torque could cause the rotor to warp unless the bolts are drastically loose on one side.
              Last edited by Nessism; 05-16-2010, 11:46 AM.
              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


                #8
                Originally posted by Turtleface View Post
                I seem to remember the ebay guy being well thought of around here. You can't cut these rotors like a normal rotor, since they're steel. You need to blanchard, or surface grind them, in order to do the job correctly. New rotors are something close to $250 or so? $45 seems pretty decent, if it's done properly. Figure $15 bucks shipping each way.
                I have used his services and was quite happy with the results. I believe Posplayr use the same service and perhaps Keith Krause? Here is the thread I started with details.

                1979 GS1000E (44 Yrs), 1981 GPz550
                Departed: 1970 Yamaha R5A, 1971 R5B, 1975 Honda XL250, 1983 Suzuki PE175, 1983 CB1100F, 1983 BMW R100RS, 1992 ST1100

                Comment


                  #9
                  Thanks for the info on that ebay guy.

                  Measured the rotors again, this time while attached to the wheel. One of the rotors was showing about .010" runout on the wheel but .005" off (measured on a surface plate). This seemed strange so the rotor was rotated 90 degrees so different holes aligned on the wheel and now I'm getting .003". Guess the wheel mounting surface is not perfect, and that was adding to the error in the rotor. At any rate, .003" seems reasonable so I'm going to try them as is and not cut them. Fingers crossed.
                  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


                    #10
                    I used Lindskog in Mass to have my stock ones done before GSXR conversion. Worked well. Cost about $45 each. http://www.lindskog.com/

                    Comment


                      #11
                      Bolt torque definately plays a role as well...I work at an automotive brake shop. Uneven bolt torque can induce several thousandths or run-out in an auto brake system. I would think that a cycle brake system, with it's smaller scale parts, would be even more inclined to do so.
                      ....
                      Matos law: Murphy was a lucky B@stard!
                      1979 GS850GN
                      sigpic

                      In memory of Dave "Gonzo" Steele
                      1975-2008

                      Comment


                        #12
                        grinding of rotors was a big subject back in the 80s in MC or cycle guide or soem top line magazine.

                        i will have to sift through my milk cartons and find an article

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