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DT125R FORUM

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  4. Can't reach top speed

Can't reach top speed

Scheduled Pinned Locked Moved Engine
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  • E Offline
    E Offline
    erionmustafa
    wrote on last edited by
    #1

    Just rebuilt it and cleaned the power valve mounted everything how it should be , but it doesn't go over 100kmh ,before the rebuild it barely did 80kmh . It's a 94 dtr 3mb engine

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    • E erionmustafa

      Just rebuilt it and cleaned the power valve mounted everything how it should be , but it doesn't go over 100kmh ,before the rebuild it barely did 80kmh . It's a 94 dtr 3mb engine

      S Offline
      S Offline
      SpookDog
      wrote on last edited by SpookDog
      #2

      @erionmustafa

      That’s a 20kph bonus! You mustafa done something right 🙂
      Jokes aside, I don’t remember your bikes history. Is it unrestricted or not?…

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      • S SpookDog

        @erionmustafa

        That’s a 20kph bonus! You mustafa done something right 🙂
        Jokes aside, I don’t remember your bikes history. Is it unrestricted or not?…

        E Offline
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        erionmustafa
        wrote on last edited by
        #3

        @SpookDog i havent done anything to it but you or someone else in the forum told me that its not restricted it has a 3NC-00 CDI i think its the unrestricted one

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        • CalumC Offline
          CalumC Offline
          Calum
          wrote on last edited by
          #4

          Is it revving out 100km/h isn't brilliant, but then my DT doesn't do much more than that 🤣 and that's fully tuned 170. It's just a question of gearing...

          Are you sure the powervalve is operating correctly? Trying just pinning it open and riding like that.

          Always Originate, Never Pirate!

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          • CalumC Calum

            Is it revving out 100km/h isn't brilliant, but then my DT doesn't do much more than that 🤣 and that's fully tuned 170. It's just a question of gearing...

            Are you sure the powervalve is operating correctly? Trying just pinning it open and riding like that.

            E Offline
            E Offline
            erionmustafa
            wrote on last edited by
            #5

            @Calum my rpm metter is broken but i will try to pin it open and do another run ,
            the speedometter is broken also im measuring it with go pro hero 9 im not sure how accurate it is

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            • E erionmustafa

              @Calum my rpm metter is broken but i will try to pin it open and do another run ,
              the speedometter is broken also im measuring it with go pro hero 9 im not sure how accurate it is

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              erionmustafa
              wrote on last edited by
              #6

              @erionmustafa i have a diamond shaped power valve can you tell me what is that for

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              • E erionmustafa

                @erionmustafa i have a diamond shaped power valve can you tell me what is that for

                S Offline
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                SpookDog
                wrote on last edited by
                #7

                @erionmustafa

                There are different shaped ends, some diamonds, some oblong. Don’t make any difference…

                You need your rev counter and speedo if you want to do any kind of comparison to what’s ‘normal’ for a given model.

                100kph is getting near the 70mph top speed for a normal, restricted dtr125…

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                • S SpookDog

                  @erionmustafa

                  There are different shaped ends, some diamonds, some oblong. Don’t make any difference…

                  You need your rev counter and speedo if you want to do any kind of comparison to what’s ‘normal’ for a given model.

                  100kph is getting near the 70mph top speed for a normal, restricted dtr125…

                  E Offline
                  E Offline
                  erionmustafa
                  wrote on last edited by
                  #8

                  @SpookDog i will get them fixed when i can but i don't think it is restricted

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                  • S SpookDog

                    @erionmustafa

                    There are different shaped ends, some diamonds, some oblong. Don’t make any difference…

                    You need your rev counter and speedo if you want to do any kind of comparison to what’s ‘normal’ for a given model.

                    100kph is getting near the 70mph top speed for a normal, restricted dtr125…

                    E Offline
                    E Offline
                    erionmustafa
                    wrote on last edited by
                    #9

                    @SpookDog but i have a square cap that i can put in 2 positions idk which way to put it to align it after

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                    • CalumC Offline
                      CalumC Offline
                      Calum
                      wrote on last edited by
                      #10

                      @erionmustafa Take the exhaust off and align the powervalve flush with the port. That's probably your problem...do that and it should rev off the clocks and be nippy...after 6k+ RPM.

                      Always Originate, Never Pirate!

                      E 1 Reply Last reply
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                      • CalumC Calum

                        @erionmustafa Take the exhaust off and align the powervalve flush with the port. That's probably your problem...do that and it should rev off the clocks and be nippy...after 6k+ RPM.

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                        erionmustafa
                        wrote on last edited by
                        #11

                        @Calum its perfectly aligned there but im thinking that the valve motor is not turning it all the way open

                        HOTSHOT IIIH 1 Reply Last reply
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                        • E erionmustafa

                          @Calum its perfectly aligned there but im thinking that the valve motor is not turning it all the way open

                          HOTSHOT IIIH Offline
                          HOTSHOT IIIH Offline
                          HOTSHOT III
                          wrote on last edited by HOTSHOT III
                          #12

                          @erionmustafa Take the pulley cover off, go for a ride and get it to operating temperature, then check PV operation with the bike running, it should do this:

                          https://www.youtube.com/watch?v=Wo_bI40UyWE&t=72s

                          Also you could try disconnecting the cables and pinning the valve temporarily like @Calum said to see if that makes a difference. I once cut down a 4mm drill bit to 35mm as a "get you home" in case of servo or PV cable issues, it's the right diameter and length to pin the valve via the pulley and alignment hole in the cylinder and can't move with the pulley cover fitted. Handy thing to have with you when out riding anyway.

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                          • E Offline
                            E Offline
                            erionmustafa
                            wrote on last edited by
                            #13

                            Thanks to all the help offered i solved the issue it was the cables not turning the valve the right way it was closing instead of oppening , tomorrow im gonna do a topspeed test thinking of hitting atleast 120-30 kmh

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