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Frame bracing, boxing vs tubing.

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    #16
    I made this with scrap metal for the boxing.
    Marc
    CIMG5560.jpg
    AIR COOLED MONSTERS NEVER DIE
    1978 GS1000C X2
    1978 GS1000E X2
    1979 GS1000S
    1979 gs1000
    1983 gs400e

    Comment


      #17
      from a flat plate to this.
      Marc
      CIMG5555.jpg
      AIR COOLED MONSTERS NEVER DIE
      1978 GS1000C X2
      1978 GS1000E X2
      1979 GS1000S
      1979 gs1000
      1983 gs400e

      Comment


        #18
        Originally posted by Buffalo Bill View Post
        Cool thread!
        Just like to know if any of these bikes were built for racing?
        Because reducing weight is important for race bikes.
        Thanks.
        If you're using a modified stock frame it's still a trade-off. Modern tyres have made frame stiffness even more important. From my experience and watching others, the period style bracing is nowhere near complete enough for modern slicks. The lower frame rails are not touched in the old model bracing. I've gussetted the area where the front crosstube joins the downtubes - and the area where the rear crosstube behind the motor joins the lower cradle tubes.
        Just folded 2mm sheet in an "L" section. This is enough to stop the front downtubes "scissoring" under lateral loads. The steering head area is better than Z1's - but that's not saying much.

        Talking to the guys involved with running the Team Classic Suzuki Katana in the IOM 2 years ago, the disadvantages of running what is actually a replica of a stock frame vs the purpose built XR69 replicas became apparent very early on. 119MPH laps represent shall we say, very large gonads.....Better suspension and geometry show up very quickly on the IOM.

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          #19
          [QUOTE=GregT;2582034] I've gussetted the area where the front crosstube joins the downtubes - and the area where the rear crosstube behind the motor joins the lower cradle tubes.
          Just folded 2mm sheet in an "L" section. This is enough to stop the front downtubes "scissoring" under lateral loads.

          Do you have a couples of pictures?
          Any help is welcome and thanks to the OP for the thread.
          I will relocate the headstock and brace the frame between the lower front crostube too.My first plan was to use 2 tubes in a V between the crosstube and the OEM bracing under the headstock.
          Marc
          AIR COOLED MONSTERS NEVER DIE
          1978 GS1000C X2
          1978 GS1000E X2
          1979 GS1000S
          1979 gs1000
          1983 gs400e

          Comment


            #20
            No, sorry lost the pics I had. Bike's at the owner's place now.
            The gussets were simple triangle folded sheet, about 50mm on a side.

            I wouldn't have thought there'd be room for an X brace under the steering head with the pipes there.

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              #21
              It will be something like this, If I have trouble with the header flange I will go with a spigot set-up.
              Marc
              skizzokat-details-3.jpg
              AIR COOLED MONSTERS NEVER DIE
              1978 GS1000C X2
              1978 GS1000E X2
              1979 GS1000S
              1979 gs1000
              1983 gs400e

              Comment


                #22
                Originally posted by kochic View Post
                It will be something like this, If I have trouble with the header flange I will go with a spigot set-up.
                Marc
                I'd still sooner go for triangular gussets under the crossmember. On the back or engine side of the downtubes.
                Lighter and simpler.

                Comment


                  #23
                  Originally posted by GregT View Post
                  I'd still sooner go for triangular gussets under the crossmember. On the back or engine side of the downtubes.
                  Lighter and simpler.
                  When you do this, do you need to switch to outside engine mounting plate?
                  Marc
                  AIR COOLED MONSTERS NEVER DIE
                  1978 GS1000C X2
                  1978 GS1000E X2
                  1979 GS1000S
                  1979 gs1000
                  1983 gs400e

                  Comment


                    #24
                    Originally posted by kochic View Post
                    When you do this, do you need to switch to outside engine mounting plate?
                    Marc
                    Looked at the pic again. Left side behind the downtube, right side in front. Won't make any difference strength wise but you won't have to change the mounts.

                    I've actually got a late 750 race motor apart here at present. Built back in the day in Australia. Big bored and hot cams. AFAIK it's done very little work - possibly just one meeting. Shows signs of being very hot indeed - and the usual lower end bearing stress signs.

                    The less interference with cooling air to the engine on those ones, the better.

                    Comment


                      #25




                      Good point about the lower frame bracing. Altough it'll mean more work to be done :-P

                      Started some cardboard templates today, will be making my plate brake tomorrow.
                      Also with these gussets it is my understanding that one does NOT weld the two short sides across the tube, just weld along the tube right?

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                        #26
                        [QUOTE
                        Also with these gussets it is my understanding that one does NOT weld the two short sides across the tube, just weld along the tube right?[/QUOTE]

                        Yes for the short side and try to fit the gas tank with the cardboard gusset to check the clearance.
                        I was not able to fit a one piece gusset there without rubbing under the tank.I made them in 3 pieces that follow the frame line once welded.
                        Marc
                        CIMG5566.jpg
                        Last edited by kochic; 01-19-2020, 02:31 PM.
                        AIR COOLED MONSTERS NEVER DIE
                        1978 GS1000C X2
                        1978 GS1000E X2
                        1979 GS1000S
                        1979 gs1000
                        1983 gs400e

                        Comment


                          #27
                          If the tubing was light gauge high tensile, yes, avoid welding across the long axis.
                          With OE frames, you're dealing with thickwall, mild steel in soft condition.
                          A short run along one side of a folded "L" section won't hurt.

                          On light gauge, you often see the tube bend toward the weld. Never seen it happen on a GS frame. I suspect they're made in stress relieved tubing.
                          Or self stress relieve with age....

                          Comment


                            #28
                            Some reading material; https://motochassis.com/Articles/Frame.mod/KawaMods.htm

                            It would seem triangulating with tubes is much preferred over gussets providing there is enough space for a tube to run right?

                            Comment


                              #29
                              not mine but you can see lower front bracing.
                              Marc
                              Attached Files
                              AIR COOLED MONSTERS NEVER DIE
                              1978 GS1000C X2
                              1978 GS1000E X2
                              1979 GS1000S
                              1979 gs1000
                              1983 gs400e

                              Comment


                                #30
                                another frame,
                                images.jpg
                                AIR COOLED MONSTERS NEVER DIE
                                1978 GS1000C X2
                                1978 GS1000E X2
                                1979 GS1000S
                                1979 gs1000
                                1983 gs400e

                                Comment

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