Skip to content
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
Skins
  • Light
  • Cerulean
  • Cosmo
  • Flatly
  • Journal
  • Litera
  • Lumen
  • Lux
  • Materia
  • Minty
  • Morph
  • Pulse
  • Sandstone
  • Simplex
  • Sketchy
  • Spacelab
  • United
  • Yeti
  • Zephyr
  • Dark
  • Cyborg
  • Darkly
  • Quartz
  • Slate
  • Solar
  • Superhero
  • Vapor

  • Default (Slate)
  • No Skin
Collapse
Brand Logo

DT125R FORUM

  1. Home
  2. Tuning
  3. Top End
  4. Time to change wheels and ...

Time to change wheels and ...

Scheduled Pinned Locked Moved Top End
47 Posts 7 Posters 9.2k Views
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • Y Offline
    Y Offline
    Yegor
    wrote on last edited by
    #9

    @declan That's great idea .

    1 Reply Last reply
    0
    • Y Offline
      Y Offline
      Yegor
      wrote on last edited by Yegor
      #10

      Hello ! Now I will try to explain my situation with photos ( sorry for my english )))

      first, I had a problem with yamaha dt lip seals ( water pump) ( the motorcycle was stopped more than half a year) , I changed it, but after that , the next day riding my bike the rear wheel suddenly blocked. Now I disarmed the cylinder and you can see whats going on. So I cant imagine why that happens , original cylinder and piston only 10000 km. And it's almost impossible to put it wrong the water pump and seal. ( or not

      • The Yamaha DT 125R cylinder is sleeved ( iron ? ) can be repaired. or go for Athena )

      • Can it be the fault of the oil pump ? how to check itยฟ ( the engine thermostat works well.)

      • ?

      0_1512589096819_IMG_20171205_172846.jpg

      0_1512589502290_IMG_20171205_172528.jpg

      0_1512589664616_IMG_20171205_163510.jpg

      Usualy I buy in Wemoto.com . Thank you in advance !

      1 Reply Last reply
      0
      • CalumC Offline
        CalumC Offline
        Calum
        wrote on last edited by
        #11

        Embed me!

        alt text

        Yeah, you can bore that out no problems.

        Ensure you modify the powervalve to the right spec. Otherwise you will risk having the powervalve come into contact with the piston.

        Always Originate, Never Pirate!

        1 Reply Last reply
        0
        • Y Offline
          Y Offline
          Yegor
          wrote on last edited by
          #12

          @Calum You mean just adjust the power valve position ? ( cables ) Thx !

          CalumC Irongamer727I 3 Replies Last reply
          0
          • Y Yegor

            @Calum You mean just adjust the power valve position ? ( cables ) Thx !

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

            @yegor No, you physically have the modify the powervalve after a rebore.

            Always Originate, Never Pirate!

            1 Reply Last reply
            0
            • Y Yegor

              @Calum You mean just adjust the power valve position ? ( cables ) Thx !

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

              @yegor Athena!

              1 Reply Last reply
              0
              • Y Yegor

                @Calum You mean just adjust the power valve position ? ( cables ) Thx !

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

                @yegor but sort out why it seized first please๐Ÿ˜‰

                1 Reply Last reply
                0
                • Y Offline
                  Y Offline
                  Yegor
                  wrote on last edited by
                  #16

                  @Calum thx again! do you know how to extract the power valve from the cylinder ? ( for cleaning and modify )

                  @Irongamer727 Ok ! )) Do you need to readjust the oil lubrication after install the Athena kit ?

                  Thx a lot .

                  Irongamer727I 1 Reply Last reply
                  0
                  • CalumC Offline
                    CalumC Offline
                    Calum
                    wrote on last edited by
                    #17

                    There is a bolt that goes through the powervalve, can be unscrewed from the front right of the cylinder. Behind the powervalve cover from the clutch cover side.

                    Always Originate, Never Pirate!

                    1 Reply Last reply
                    0
                    • Y Yegor

                      @Calum thx again! do you know how to extract the power valve from the cylinder ? ( for cleaning and modify )

                      @Irongamer727 Ok ! )) Do you need to readjust the oil lubrication after install the Athena kit ?

                      Thx a lot .

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

                      @yegor some go premix some don't. I will go with the pump when installing my kit

                      1 Reply Last reply
                      0
                      • J Offline
                        J Offline
                        Jens Eskildsen
                        wrote on last edited by
                        #19

                        A slight rebore shouldn't affect the powervalve ๐Ÿ™‚

                        CalumC 1 Reply Last reply
                        0
                        • J Jens Eskildsen

                          A slight rebore shouldn't affect the powervalve ๐Ÿ™‚

                          CalumC Offline
                          CalumC Offline
                          Calum
                          wrote on last edited by
                          #20

                          @jens-eskildsen Yes it will.

                          If the bore is stock (getting rarer these days and not worth assuming) then no, you're right. But once you start going over the first rebore size, modifying the valve is a must.

                          To save confusing, I said modify the valve just as a precaution.

                          Always Originate, Never Pirate!

                          1 Reply Last reply
                          0
                          • Y Offline
                            Y Offline
                            Yegor
                            wrote on last edited by
                            #21

                            Yes, the cylinder was rebored at least once. Now I'm looking where do that again. Thx !!

                            @Calum > ?
                            0_1512655186767_IMG_20171205_163718.jpg

                            CalumC 1 Reply Last reply
                            0
                            • Y Yegor

                              Yes, the cylinder was rebored at least once. Now I'm looking where do that again. Thx !!

                              @Calum > ?
                              0_1512655186767_IMG_20171205_163718.jpg

                              CalumC Offline
                              CalumC Offline
                              Calum
                              wrote on last edited by
                              #22

                              @yegor Yeah that's the pup.

                              Always Originate, Never Pirate!

                              1 Reply Last reply
                              0
                              • Y Offline
                                Y Offline
                                Yegor
                                wrote on last edited by
                                #23

                                @Calum **thanks to everyone ** . One question ( maybe a little bit stupid) XD . What material the cylinder is made of ? And the cylinder sleeve ? ( Yamaha DT 125R )

                                The cylinder sleeve Iron?
                                Cylinder Aluminium ?

                                Have you tuned Yamaha cylinder ? ( admision / exhaust transfers etc ?)

                                Cheers !

                                CalumC 1 Reply Last reply
                                0
                                • Y Yegor

                                  @Calum **thanks to everyone ** . One question ( maybe a little bit stupid) XD . What material the cylinder is made of ? And the cylinder sleeve ? ( Yamaha DT 125R )

                                  The cylinder sleeve Iron?
                                  Cylinder Aluminium ?

                                  Have you tuned Yamaha cylinder ? ( admision / exhaust transfers etc ?)

                                  Cheers !

                                  CalumC Offline
                                  CalumC Offline
                                  Calum
                                  wrote on last edited by
                                  #24

                                  @yegor YEah that's correct. I imagine the bore will be a steel alloy.

                                  I've had my barrel ported by a tuner.

                                  Always Originate, Never Pirate!

                                  declanD 1 Reply Last reply
                                  0
                                  • CalumC Calum

                                    @yegor YEah that's correct. I imagine the bore will be a steel alloy.

                                    I've had my barrel ported by a tuner.

                                    declanD Offline
                                    declanD Offline
                                    declan
                                    wrote on last edited by
                                    #25

                                    @calum how much did that cost bud and can it just bolt back on no jet changes etc

                                    CalumC 1 Reply Last reply
                                    0
                                    • declanD declan

                                      @calum how much did that cost bud and can it just bolt back on no jet changes etc

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

                                      @declan No, porting is going to drastically change the characteristics of a two stroke engine.

                                      I wouldn't advise it on a daily, or on stock ignition.

                                      You don't get something for nothing. I'm not going into it here, but the principle is, peak almost always alters performance elsewhere, usually torque.

                                      There are exceptions where engines are poorly designed and modifications improve performance with no effect. But the end of it is, these engines are pretty well designed. When it comes to porting them, you're making a sacrafice somewhere else in the rev range for more power.

                                      Always Originate, Never Pirate!

                                      1 Reply Last reply
                                      1
                                      • Y Offline
                                        Y Offline
                                        Yegor
                                        wrote on last edited by
                                        #27

                                        Hello ) !
                                        I will go tomorrow to the workshop with the cylinder for bore. I know is privileged information and long testing time but do you know where I can find information about tuning cylinder transfers, I think is good idea do something there before it will be bored. Maybe in the same workshop they do that for extra โ‚ฌ, will ask.

                                        all this marked with color dots can be modified/enlarged : ?
                                        0_1513007430177_cilindro marcado.jpg
                                        at the top of ALL the transfers: (?)
                                        0_1513007813829_IMG_20171205_163907.jpg

                                        so, thank you again for the help, and gas gas !

                                        1 Reply Last reply
                                        0
                                        • CalumC Offline
                                          CalumC Offline
                                          Calum
                                          wrote on last edited by
                                          #28

                                          Depending on how good your English reading is, I HIGHLY recommend Graham Bell's Two Stroke Performance Tuning.

                                          That will give you a lot of knowledge on tuning two strokes.

                                          I would NOT recommend porting the barrel, or altering the port timings, without a programmable CDI.

                                          Always Originate, Never Pirate!

                                          1 Reply Last reply
                                          0
                                          Reply
                                          • Reply as topic
                                          Log in to reply
                                          • Oldest to Newest
                                          • Newest to Oldest
                                          • Most Votes


                                          • Login

                                          • Don't have an account? Register

                                          • Login or register to search.
                                          • First post
                                            Last post
                                          0
                                          • Recent
                                          • Tags
                                          • Popular
                                          • Users
                                          • Groups