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DT125R FORUM

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  4. Time to change wheels and ...

Time to change wheels and ...

Scheduled Pinned Locked Moved Top End
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  • Y Yegor

    Hello friends !

    Finnaly I've recived the piston. While they still fix the cylinder, I am reading carburation manuals and cleaning the Mikuni. I'll buy carburetor jet kit from 180 to 250.

    I have noticed that the Yamaha piston rings are different while the Wossner ones are the same:
    0_1514472080448_26177755_10214388893254589_184702224_o.jpg

    The Small End Bearing is 17mm ( the one that was put ) but the original bearing for Yamaha piston is 19.5 mm, so is very important replace it ?
    0_1514472465753_26179304_10214388983376842_1813155606_o.jpg

    And I see that the Wossner piston does not have holes that lubricate the gudgeon pin:
    0_1514472779932_26237588_10214388991897055_396085839_o.jpg

    ( it might be a good idea to do them? although I do not think so ) )

    I have a base gasket but the Genuine Base Gasket it is made of metal (aluminium?) , so It is highly recommended put the metal one ?

    uf a lot of questions but thank you in advance . :man_biking_tone1:

    declanD Offline
    declanD Offline
    declan
    wrote on last edited by
    #34

    @yegor as far as I know stock bikes don’t have the metal base gasket I wouldn’t bother with the lubrication hole if it was needed they would of already done it

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    • CalumC Offline
      CalumC Offline
      Calum
      wrote on last edited by
      #35

      OEM gaskets are far superior, but Athena gaskets are perfectly good. You MUST use either genuine or Athena for the head gasket. The base gasket doesn't matter.

      Be sure to measure the piston ring end gaps on those wossner rings. I have never had a set that were perfect, they've always needed fettling.

      Always Originate, Never Pirate!

      1 Reply Last reply
      0
      • terry.tzT Offline
        terry.tzT Offline
        terry.tz
        wrote on last edited by
        #36

        @yegor said in Time to change wheels and ...:

        http://www.2strokeengine.net/gordonjennings/twostroketunershandbook.php

        I have read this and I would say read something else after reading it to put information in a better order for understanding

        "Muddy water is best cleared by leaving it alone" Alan Watts

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        • Y Offline
          Y Offline
          Yegor
          wrote on last edited by Yegor
          #37

          @declan ok thanks, I think the same. But in PJME you can find the Genuine Yamaha base gasket and is the same that I have , made of metal ( I think steel )
          http://www.pjme.co.uk/acatalog/4FU-11351-00.jpg

          @Calum thx , I will pay attention to ring end gaps. And have bought the Athena head gasket and the original yamaha water pump radial shaft seal.

          @terry-tz Thanks , will try read it in English ( I'm from Spain) , and find some literature in spanish.

          Now I have disassembled the carburetor and I have understood much better how it works and how they connect the holes. this video helped me a lot:
          Chicho Lorenzo ( Lorenzo's father MotoGP)
          https://www.youtube.com/watch?v=niNn0LZESfg

          My questions are. Our Mikuni carb ( TM 28 ) main original jet is 180 ?
          in this webpage you can see specs and the main jet is 180 .
          -> https://www.japanbaiku.com/mikuni/mikuni-tm/mikuni-tm28

          . Now I have seen that I have 240 all this time , without problems. With the Romeu exhaust will try with 250/260. BUT this jet :
          https://www.japanbaiku.com/image/cache/data/chicles_tornillos/kys-00b-500x500.jpg <--- ralenti/starter jet ? the original is 15 . will try 17.5

          where do you buy jets kit ? www.japanbaiku.com is a little bit expensive.

          Thanks in advance !

          CalumC 1 Reply Last reply
          0
          • Y Yegor

            @declan ok thanks, I think the same. But in PJME you can find the Genuine Yamaha base gasket and is the same that I have , made of metal ( I think steel )
            http://www.pjme.co.uk/acatalog/4FU-11351-00.jpg

            @Calum thx , I will pay attention to ring end gaps. And have bought the Athena head gasket and the original yamaha water pump radial shaft seal.

            @terry-tz Thanks , will try read it in English ( I'm from Spain) , and find some literature in spanish.

            Now I have disassembled the carburetor and I have understood much better how it works and how they connect the holes. this video helped me a lot:
            Chicho Lorenzo ( Lorenzo's father MotoGP)
            https://www.youtube.com/watch?v=niNn0LZESfg

            My questions are. Our Mikuni carb ( TM 28 ) main original jet is 180 ?
            in this webpage you can see specs and the main jet is 180 .
            -> https://www.japanbaiku.com/mikuni/mikuni-tm/mikuni-tm28

            . Now I have seen that I have 240 all this time , without problems. With the Romeu exhaust will try with 250/260. BUT this jet :
            https://www.japanbaiku.com/image/cache/data/chicles_tornillos/kys-00b-500x500.jpg <--- ralenti/starter jet ? the original is 15 . will try 17.5

            where do you buy jets kit ? www.japanbaiku.com is a little bit expensive.

            Thanks in advance !

            CalumC Offline
            CalumC Offline
            Calum
            wrote on last edited by
            #38

            @yegor Hi bud,

            240 main jet is fine, in your climate it probably about right. In colder climates then you would want to up jet slightly.

            Jets are expensive, I cannot stress enough how important it is to buy genuine jets from reputable sellers.

            Always Originate, Never Pirate!

            1 Reply Last reply
            0
            • terry.tzT Offline
              terry.tzT Offline
              terry.tz
              wrote on last edited by
              #39

              @Yegor if your Spanish don't bother reading that old notebook crap it got everything you need to know but badly rote and explain get something in your native tongue

              "Muddy water is best cleared by leaving it alone" Alan Watts

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              0
              • Y Offline
                Y Offline
                Yegor
                wrote on last edited by
                #40

                @calum yes. those are original Mikuni jets. But what size is the ralenti jet ? 25 or 15 or what ?

                ( https://www.japanbaiku.com/image/cache/data/chicles_tornillos/kys-00b-500x500.jpg ) thx!

                CalumC 1 Reply Last reply
                0
                • Y Yegor

                  @calum yes. those are original Mikuni jets. But what size is the ralenti jet ? 25 or 15 or what ?

                  ( https://www.japanbaiku.com/image/cache/data/chicles_tornillos/kys-00b-500x500.jpg ) thx!

                  CalumC Offline
                  CalumC Offline
                  Calum
                  wrote on last edited by
                  #41

                  @yegor Pretty sure that's called the atomiser. No idea what a ralenti jet is, neither do I know what size it is. I don't run a mikuni carburetor so I cannot help you I am afraid.

                  Always Originate, Never Pirate!

                  1 Reply Last reply
                  0
                  • Y Offline
                    Y Offline
                    Yegor
                    wrote on last edited by
                    #42

                    @calum I was researching. I think in english is called " Pilot jet " and Mikuni TM28 pilot jet size is 15.

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                    0
                    • Y Offline
                      Y Offline
                      Yegor
                      wrote on last edited by
                      #43

                      sorry, the DT 125 "R" version is 17,5 pilot jet.

                      1 Reply Last reply
                      0
                      • Y Offline
                        Y Offline
                        Yegor
                        wrote on last edited by Yegor
                        #44

                        Hello, I don't know if is good idea to write in this thread . Today I was checking the oil pump and I realized that the color of the oil changed: it has a suspicious color )
                        ( I have put a transparent tube to check the oil flow)
                        0_1518129315115_27901538_10214764034192878_1048204166_o.jpg
                        I think it's because of oil seal or o'ring
                        0_1518129996122_27783450_10214764084834144_352994660_n.jpg
                        11. O-RING
                        -- 13. OIL SEAL

                        WHat do you think ? Thanks in advance

                        1 Reply Last reply
                        0
                        • CalumC Offline
                          CalumC Offline
                          Calum
                          wrote on last edited by
                          #45

                          Is the pipe suitable for oil?

                          Always Originate, Never Pirate!

                          Y 1 Reply Last reply
                          0
                          • CalumC Calum

                            Is the pipe suitable for oil?

                            Y Offline
                            Y Offline
                            Yegor
                            wrote on last edited by Yegor
                            #46

                            @calum said in Time to change wheels and ...:

                            pipe

                            you mean that if the material the tube is made of is the right one ? the #3 in the picture.

                            I put the tube yesterday to check the pump, later I will put the original. I'm going to add oil to the gas tank. 100 ml of oil for 5L gas. ?
                            with new cilinder and piston ...

                            I started the bike yesterday after installing the piston

                            CalumC 1 Reply Last reply
                            0
                            • Y Yegor

                              @calum said in Time to change wheels and ...:

                              pipe

                              you mean that if the material the tube is made of is the right one ? the #3 in the picture.

                              I put the tube yesterday to check the pump, later I will put the original. I'm going to add oil to the gas tank. 100 ml of oil for 5L gas. ?
                              with new cilinder and piston ...

                              I started the bike yesterday after installing the piston

                              CalumC Offline
                              CalumC Offline
                              Calum
                              wrote on last edited by
                              #47

                              @yegor Yeah, it's gotta be suitable for oil.

                              Always Originate, Never Pirate!

                              1 Reply Last reply
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