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DT125R FORUM

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  4. Dt125 mikuni carb

Dt125 mikuni carb

Scheduled Pinned Locked Moved Carburetor
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  • K kevin

    :311670245943 eBay item no.
    No I didn’t mean the yeis bottle I was referring to the other one on the air box side of the carb.

    Irongamer727I Offline
    Irongamer727I Offline
    Irongamer727
    wrote on last edited by
    #7

    @kevin
    https://imgur.com/gallery/bGFxgyY

    1 Reply Last reply
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    • Irongamer727I Offline
      Irongamer727I Offline
      Irongamer727
      wrote on last edited by
      #8

      Is is this one?

      K 1 Reply Last reply
      0
      • Irongamer727I Irongamer727

        Is is this one?

        K Offline
        K Offline
        kevin
        wrote on last edited by
        #9

        Yes that’s the one. l would love to see the maths behind it,unfortunately dtpedia.de doesn’t mention it when referring to the vergaser or carburettor as we know it.

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        • Irongamer727I Offline
          Irongamer727I Offline
          Irongamer727
          wrote on last edited by
          #10

          @Calum is it really a restrictor?

          CalumC 1 Reply Last reply
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          • Irongamer727I Irongamer727

            @Calum is it really a restrictor?

            CalumC Offline
            CalumC Offline
            Calum
            wrote on last edited by
            #11

            @irongamer727 Not to my knowledge, the little box on the side of the air box can also be found on the competition bike WR200, they wouldn't restrict a competition bike. At least that's what @AndyYam told me. And he has a lot of experience with all of that.

            Secondly, the PowerJet, to my knowledge (Happy to be corrected) is a clever mechanism to lean the fuel off at wide open throttle, when actually you don't need as much fuel.

            The logic is that at WOT, you should be easing off the load of the engine and now it's all about refining that combustible mix. The leaner you can run that engine, the better the burn of combustible mix can be.

            The trick is to lean it off as much as possible, without causing detonation.

            Always Originate, Never Pirate!

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            • Glynn123G Offline
              Glynn123G Offline
              Glynn123
              wrote on last edited by
              #12

              Removed that little airbox bottle on mine, can't say I noticed any difference but bike runs strong with pleanty pull with it removed and plugged.

              CalumC 1 Reply Last reply
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              • Glynn123G Glynn123

                Removed that little airbox bottle on mine, can't say I noticed any difference but bike runs strong with pleanty pull with it removed and plugged.

                CalumC Offline
                CalumC Offline
                Calum
                wrote on last edited by
                #13

                @glynn123 There are better ways to restrict the bike than some plastic box on the inlet tract lol.

                I don't know the science behind it, I figured it would work in a similar fashion to the YEIS. But it's as mystery.

                The DTRE also had YAIS as well.

                Always Originate, Never Pirate!

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                • Irongamer727I Offline
                  Irongamer727I Offline
                  Irongamer727
                  wrote on last edited by
                  #14

                  My Haynes manual says stock pilot jet fit the Dtx is 17.5? What the hell? Thought it was 25.

                  K 1 Reply Last reply
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                  • Irongamer727I Irongamer727

                    My Haynes manual says stock pilot jet fit the Dtx is 17.5? What the hell? Thought it was 25.

                    K Offline
                    K Offline
                    kevin
                    wrote on last edited by
                    #15

                    @irongamer727 first flatslides came with 22.5 and later models 17.5 and 210 mainjet

                    Irongamer727I 1 Reply Last reply
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                    • K kevin

                      @irongamer727 first flatslides came with 22.5 and later models 17.5 and 210 mainjet

                      Irongamer727I Offline
                      Irongamer727I Offline
                      Irongamer727
                      wrote on last edited by
                      #16

                      @kevin Alright, thx

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                      • Irongamer727I Offline
                        Irongamer727I Offline
                        Irongamer727
                        wrote on last edited by
                        #17

                        So I was finally able to unscrew my pilot jet for my dtx. It is a nightmare to start now with the Athena kit. I looked in the Haynes manual and it claimed stock pilot jet for the dtx was 17.5.
                        Mine was a 35! What on earth? How is it possible it is hard to start NOW and not when it was 100% stock?

                        Pilot jet size 35 https://imgur.com/gallery/fS02dV8

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                        • Irongamer727I Offline
                          Irongamer727I Offline
                          Irongamer727
                          wrote on last edited by
                          #18

                          Either way, it is too big right?

                          1 Reply Last reply
                          0
                          • Irongamer727I Offline
                            Irongamer727I Offline
                            Irongamer727
                            wrote on last edited by
                            #19

                            Response please...

                            K 1 Reply Last reply
                            0
                            • CalumC Offline
                              CalumC Offline
                              Calum
                              wrote on last edited by
                              #20

                              Ask any tuner how to set up a carburettor and you'll get the same response.

                              It depends on your setup.

                              Everything from Atmospheric conditions to state of the engine and even altitude will affect jetting.

                              It's imperative that ones carb is tuned to these varying conditions.

                              20 years ago, Yamaha spent thousands on designing the perfect carburettor settings to get the DT roughly in the right ball park.

                              The moment you started modifying the bike, you throw all of Yamaha's hard work out the window.

                              Just because it had some ridiculous settings on it, doesn't necessarily mean it was wrong.

                              Jetting should be done to suit, and there is reams of guides on here to help you get the bike in right area.

                              Always Originate, Never Pirate!

                              Irongamer727I 1 Reply Last reply
                              0
                              • CalumC Calum

                                Ask any tuner how to set up a carburettor and you'll get the same response.

                                It depends on your setup.

                                Everything from Atmospheric conditions to state of the engine and even altitude will affect jetting.

                                It's imperative that ones carb is tuned to these varying conditions.

                                20 years ago, Yamaha spent thousands on designing the perfect carburettor settings to get the DT roughly in the right ball park.

                                The moment you started modifying the bike, you throw all of Yamaha's hard work out the window.

                                Just because it had some ridiculous settings on it, doesn't necessarily mean it was wrong.

                                Jetting should be done to suit, and there is reams of guides on here to help you get the bike in right area.

                                Irongamer727I Offline
                                Irongamer727I Offline
                                Irongamer727
                                wrote on last edited by
                                #21

                                @calum guess so. Only way is to buy and try stuff I guess

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                                • Irongamer727I Irongamer727

                                  Response please...

                                  K Offline
                                  K Offline
                                  kevin
                                  wrote on last edited by
                                  #22

                                  @irongamer727 I’m a firm believer in leaving things the way they are and not thinking I’m better than the designers.
                                  To answer your question 35 is very big for your carb.
                                  Does Athena give any tips on resetting.
                                  You say it’s hard to start, have you checked the fuel feed pipe when the cold start lever is on as it’s very narrow and often gets blocked.

                                  Irongamer727I 1 Reply Last reply
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                                  • K kevin

                                    @irongamer727 I’m a firm believer in leaving things the way they are and not thinking I’m better than the designers.
                                    To answer your question 35 is very big for your carb.
                                    Does Athena give any tips on resetting.
                                    You say it’s hard to start, have you checked the fuel feed pipe when the cold start lever is on as it’s very narrow and often gets blocked.

                                    Irongamer727I Offline
                                    Irongamer727I Offline
                                    Irongamer727
                                    wrote on last edited by
                                    #23

                                    @kevin nope. Athena don't give any recommendations at all. Do you mean the fuel hose itself? That's brand new. The choke works, could there be some debris in the mechanism you think?

                                    K 1 Reply Last reply
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                                    • Irongamer727I Irongamer727

                                      @kevin nope. Athena don't give any recommendations at all. Do you mean the fuel hose itself? That's brand new. The choke works, could there be some debris in the mechanism you think?

                                      K Offline
                                      K Offline
                                      kevin
                                      wrote on last edited by
                                      #24

                                      @irongamer727 thin brass pipe near to the hole the pilot jet drops in is the fuel pipe whilst on the choke cycle, very thin wire needs poking down to the bottom and then through the cross holes.

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                                      • Irongamer727I Offline
                                        Irongamer727I Offline
                                        Irongamer727
                                        wrote on last edited by
                                        #25

                                        Alright so as I'm getting progressively better at them wheelies and can ride longer, I've noticed stuff. The carb wants to piss out the transparent liquid gold (petrol).

                                        Is tilting the carb the only way to go? Or could a float adjustment do the trick?

                                        CalumC 1 Reply Last reply
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                                        • Irongamer727I Irongamer727

                                          Alright so as I'm getting progressively better at them wheelies and can ride longer, I've noticed stuff. The carb wants to piss out the transparent liquid gold (petrol).

                                          Is tilting the carb the only way to go? Or could a float adjustment do the trick?

                                          CalumC Offline
                                          CalumC Offline
                                          Calum
                                          wrote on last edited by
                                          #26

                                          @irongamer727 Sounds like the flat is causing you issues.

                                          Always Originate, Never Pirate!

                                          Irongamer727I 1 Reply Last reply
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