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DT125R FORUM

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  4. About to perform a fork oil change (not Dt125)

About to perform a fork oil change (not Dt125)

Scheduled Pinned Locked Moved Suspension
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  • Irongamer727I Irongamer727

    @NINJA Found simular information on a forum. How do I need to hold the fork? Put it in a vice with it just sitting?

    MiniaM Offline
    MiniaM Offline
    Minia
    wrote on last edited by Minia
    #10

    @Irongamer727 said in About to perform a fork oil change (not Dt125):

    @NINJA Found simular information on a forum. How do I need to hold the fork? Put it in a vice with it just sitting?

    Yup, soft jaws or a rag and just sit in in the vice and crack the nut and let the old stuff pour out.

    Yamaha DT125R Blue 2002, XT 125 1982, Yamaha WR250Z 1992, BMW GS650F 1994, Benelli BN302 2015

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    • J Offline
      J Offline
      Jens Eskildsen
      wrote on last edited by Jens Eskildsen
      #11

      Its easier to uninstall the cap when the forks are still mounted. Make sure to loosen the pinchbolts in the upper tripleclamb first.

      And yes, the 102 sounds like 102mm from the top of the compressed fork (without spring installed) to the oil.

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      1
      • CalumC Offline
        CalumC Offline
        Calum
        wrote on last edited by
        #12

        Easiest way is to pour the oil into a measuring jug and see how much came out.

        Always Originate, Never Pirate!

        Irongamer727I 1 Reply Last reply
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        • CalumC Calum

          Easiest way is to pour the oil into a measuring jug and see how much came out.

          Irongamer727I Offline
          Irongamer727I Offline
          Irongamer727
          wrote on last edited by
          #13

          @Calum though you never know if someone else has filled the wrong amount of oil previously.

          CalumC 1 Reply Last reply
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          • Irongamer727I Irongamer727

            @Calum though you never know if someone else has filled the wrong amount of oil previously.

            CalumC Offline
            CalumC Offline
            Calum
            wrote on last edited by
            #14

            @Irongamer727 Be alreet. I'm assuming you've been riding the bike and it's not been a problem

            Always Originate, Never Pirate!

            Irongamer727I 1 Reply Last reply
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            • CalumC Calum

              @Irongamer727 Be alreet. I'm assuming you've been riding the bike and it's not been a problem

              Irongamer727I Offline
              Irongamer727I Offline
              Irongamer727
              wrote on last edited by
              #15

              @Calum yeah I guess. Probably going ride the bike pretty hard with stupid wheelies during the summer. Do you want just slightly more oil then? Or just the specified level?

              NINJAN 1 Reply Last reply
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              • Irongamer727I Irongamer727

                @Calum yeah I guess. Probably going ride the bike pretty hard with stupid wheelies during the summer. Do you want just slightly more oil then? Or just the specified level?

                NINJAN Offline
                NINJAN Offline
                NINJA
                wrote on last edited by
                #16

                @Irongamer727 I would stick with the specified amount, if you want the forks to be a bit stiffer, then just use thicker oil like 15-20 grade.

                SEDUCED BY THE DARK SIDE!!!

                CalumC 1 Reply Last reply
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                • NINJAN NINJA

                  @Irongamer727 I would stick with the specified amount, if you want the forks to be a bit stiffer, then just use thicker oil like 15-20 grade.

                  CalumC Offline
                  CalumC Offline
                  Calum
                  wrote on last edited by
                  #17

                  @NINJA Did we discuss this on another thread??? And thicker oil doesn't affect stiffness. I distinctly remember @Jens-Eskildsen Saying something. Or someone like that.

                  I think, if you want stiffer suspension, then you need to change the springs.

                  Always Originate, Never Pirate!

                  NINJAN MiniaM 2 Replies Last reply
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                  • CalumC Calum

                    @NINJA Did we discuss this on another thread??? And thicker oil doesn't affect stiffness. I distinctly remember @Jens-Eskildsen Saying something. Or someone like that.

                    I think, if you want stiffer suspension, then you need to change the springs.

                    NINJAN Offline
                    NINJAN Offline
                    NINJA
                    wrote on last edited by
                    #18

                    @Calum Probably we go around in circles a lot on this forum!!! :grinning_face_with_smiling_eyes: :smiling_face_with_open_mouth_closed_eyes: :smiling_face_with_open_mouth_cold_sweat: :face_with_tears_of_joy: 🤣

                    SEDUCED BY THE DARK SIDE!!!

                    CalumC 1 Reply Last reply
                    0
                    • NINJAN NINJA

                      @Calum Probably we go around in circles a lot on this forum!!! :grinning_face_with_smiling_eyes: :smiling_face_with_open_mouth_closed_eyes: :smiling_face_with_open_mouth_cold_sweat: :face_with_tears_of_joy: 🤣

                      CalumC Offline
                      CalumC Offline
                      Calum
                      wrote on last edited by
                      #19

                      @NINJA I can't remember.

                      Genuinely, as bad as this might sound, sometimes I actually struggle to recognise dreams from real life.

                      I've sat there at times thinking of something as if it actually happened. Only to remember it was a dream. Mental mate.

                      Always Originate, Never Pirate!

                      NINJAN 1 Reply Last reply
                      1
                      • CalumC Calum

                        @NINJA I can't remember.

                        Genuinely, as bad as this might sound, sometimes I actually struggle to recognise dreams from real life.

                        I've sat there at times thinking of something as if it actually happened. Only to remember it was a dream. Mental mate.

                        NINJAN Offline
                        NINJAN Offline
                        NINJA
                        wrote on last edited by NINJA
                        #20

                        @Calum You gotta stay off them drugs dude, I keep telling ya that there no good for ya!!! :grinning_face_with_smiling_eyes: :smiling_face_with_open_mouth_closed_eyes: :smiling_face_with_open_mouth_cold_sweat: :face_with_tears_of_joy: 🤣

                        But back on topic; I believe that the thicker oil slows the compression down, as it is harder to compress through the valves? Which in turn makes the forks slightly stiffer? But I may be wrong? And you are correct - Ultimately stiffer or progressive springs are the sure way to stiffen or upgrade their damping qualities. 😉

                        SEDUCED BY THE DARK SIDE!!!

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                        • CalumC Offline
                          CalumC Offline
                          Calum
                          wrote on last edited by
                          #21

                          This site has some good advice
                          https://advrider.com/f/threads/fork-oil-weight-change-whats-it-do.997592/

                          @NINJA It looks like the general consensus is that you're changing the dampening and rebound rate, not the same as stiffness.

                          Resulting affects are, yes it'll be harder to compress, but the inverse is also true. It won't rebound as quick. Sounds a bit deadly if you ask me.

                          Always Originate, Never Pirate!

                          NINJAN 1 Reply Last reply
                          0
                          • CalumC Calum

                            @NINJA Did we discuss this on another thread??? And thicker oil doesn't affect stiffness. I distinctly remember @Jens-Eskildsen Saying something. Or someone like that.

                            I think, if you want stiffer suspension, then you need to change the springs.

                            MiniaM Offline
                            MiniaM Offline
                            Minia
                            wrote on last edited by
                            #22

                            @Calum said in About to perform a fork oil change (not Dt125):

                            @NINJA Did we discuss this on another thread??? And thicker oil doesn't affect stiffness. I distinctly remember @Jens-Eskildsen Saying something. Or someone like that.

                            I think, if you want stiffer suspension, then you need to change the springs.

                            If you want stiffer suspension with DT forks, you've got 2 choices. The better one, is to change the springs. The cheaper and alternative method is to fill the forks up more. Thicker oil will only affect the damping rate, I.E it would slow down your rebound rate. Afterall you cannot pressurise a liquid. What allows the fork to travel and suspend movement is the air inside. Increase the quantity of oil, you reduce the amount of air and therefore require more energy to move the extra density of oil.

                            Now I've never taken the DT forks apart so I genuinely don't know how much room you have to play with. But I can say if you're trying to get your suspension right for your bodyweight and leg height, it is a lengthy and arduous process! Took me a few days to get right on the GasGas.

                            Yamaha DT125R Blue 2002, XT 125 1982, Yamaha WR250Z 1992, BMW GS650F 1994, Benelli BN302 2015

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                            • CalumC Calum

                              This site has some good advice
                              https://advrider.com/f/threads/fork-oil-weight-change-whats-it-do.997592/

                              @NINJA It looks like the general consensus is that you're changing the dampening and rebound rate, not the same as stiffness.

                              Resulting affects are, yes it'll be harder to compress, but the inverse is also true. It won't rebound as quick. Sounds a bit deadly if you ask me.

                              NINJAN Offline
                              NINJAN Offline
                              NINJA
                              wrote on last edited by
                              #23

                              @Calum I used to do it all the time on my mountain bikes Rock Shox, they did change as you have suggested tho. I never had any problems and the forks were much better after the thicker oil was added.

                              SEDUCED BY THE DARK SIDE!!!

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                              • T Offline
                                T Offline
                                theportingmaster
                                wrote on last edited by
                                #24

                                486ml + or - 2.5ml so just under 1/2 a litre of oil.

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