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DT125R FORUM

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  3. Bike lacks power

Bike lacks power

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  • CalumC Calum

    Sounds like the powervalve to me. Or the reed switch. It should pull hard to the red line.

    Lightening the flywheel won't help.

    Ryan FR Offline
    Ryan FR Offline
    Ryan F
    wrote on last edited by
    #9

    @Calum I did disconnected the servo and run it pinned fully open it was alot better and pulled all the way from rouhgly 7K to like 11K but I can't stand the lack of bottom end power after the powervalve is pinned.

    So I have reconnected it again and It's just not as quick up top from what I can tell I have set it up properly the diamond lines up with the hole and once you rev the bike onto powerband that is where the diamond moves too. Could it be the servo itself? it still makes the noise when you turn the igntion on.

    The reed switch is disconnected I left it behind the clocks though.

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    • declanD declan

      @Ryan-F the 3mb head is ideal but hard to find since everyone wants them you can get your head de restricted if the powers dropping off like that I’d bet it’s the powervalve set set correctly

      Ryan FR Offline
      Ryan FR Offline
      Ryan F
      wrote on last edited by
      #10

      @declan they are a few ebay but they are quite pricey, was going to see if any shops near me would de-restrict it for me

      declanD 1 Reply Last reply
      0
      • Ryan FR Ryan F

        @declan they are a few ebay but they are quite pricey, was going to see if any shops near me would de-restrict it for me

        declanD Offline
        declanD Offline
        declan
        wrote on last edited by
        #11

        @Ryan-F well you have your issue then it’s the powervalve yeah an engine porter should be able to do it no problem, the powervalve should whine as you turn the key if it doesn’t then there’s an issue the valve should be aligned through the exhaust port so that it’s a smooth transition as you look through the exhaust port there should be no step or ridge

        CalumC Ryan FR 2 Replies Last reply
        0
        • declanD declan

          @Ryan-F well you have your issue then it’s the powervalve yeah an engine porter should be able to do it no problem, the powervalve should whine as you turn the key if it doesn’t then there’s an issue the valve should be aligned through the exhaust port so that it’s a smooth transition as you look through the exhaust port there should be no step or ridge

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

          @declan The issue being on the new models the powervalve retards after 8K RPM. Starving the engine of the power.

          Getting an older CDI unit, or an aftermarket one, would rectify this.

          Always Originate, Never Pirate!

          declanD 1 Reply Last reply
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          • CalumC Calum

            @declan The issue being on the new models the powervalve retards after 8K RPM. Starving the engine of the power.

            Getting an older CDI unit, or an aftermarket one, would rectify this.

            declanD Offline
            declanD Offline
            declan
            wrote on last edited by
            #13

            @Calum but it’s alreday revving freely so surely the cdi isn’t the issue I though if the cdi were restricted it would only rev to 9k like mine

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

              The later CDIs control the powervalve servo. On crossers, the powervalve is controlled by the gearbox, or by exhaust pressure. On the DT it's controlled via the YPVS CDI. Early models this was separate from the CDI. Later models it was an all in one.

              Always Originate, Never Pirate!

              Ryan FR 1 Reply Last reply
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              • CalumC Calum

                The later CDIs control the powervalve servo. On crossers, the powervalve is controlled by the gearbox, or by exhaust pressure. On the DT it's controlled via the YPVS CDI. Early models this was separate from the CDI. Later models it was an all in one.

                Ryan FR Offline
                Ryan FR Offline
                Ryan F
                wrote on last edited by
                #15

                @Calum Is there a year roughly I would need to buy? and would I need a new loom or would it just be a case of wire it up and it's ready to go?

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                • declanD declan

                  @Ryan-F well you have your issue then it’s the powervalve yeah an engine porter should be able to do it no problem, the powervalve should whine as you turn the key if it doesn’t then there’s an issue the valve should be aligned through the exhaust port so that it’s a smooth transition as you look through the exhaust port there should be no step or ridge

                  Ryan FR Offline
                  Ryan FR Offline
                  Ryan F
                  wrote on last edited by
                  #16

                  @declan Yeah the power valve works and wines as I turn the ignition I will have to look into what callum said about an old or aftermarket CDI, I was just scratching my head a little as it all seemed ok

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

                    @declan said in Bike lacks power:

                    m

                    It's like a 3RM model CDI. But to be honest, just get a Zeeltronic for it. It'll be better in the long run since it will be new, rather than buying something old and potentially faulty.

                    https://www.thetuningworks.co.uk/store/product_info.php?products_id=1268

                    £165

                    Always Originate, Never Pirate!

                    Ryan FR 1 Reply Last reply
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                    • CalumC Calum

                      @declan said in Bike lacks power:

                      m

                      It's like a 3RM model CDI. But to be honest, just get a Zeeltronic for it. It'll be better in the long run since it will be new, rather than buying something old and potentially faulty.

                      https://www.thetuningworks.co.uk/store/product_info.php?products_id=1268

                      £165

                      Ryan FR Offline
                      Ryan FR Offline
                      Ryan F
                      wrote on last edited by
                      #18

                      @Calum Ok thank you, do they come with like a base map at least?

                      was looking at getting another top end and getting it ported also.

                      CalumC 1 Reply Last reply
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                      • Ryan FR Ryan F

                        @Calum Ok thank you, do they come with like a base map at least?

                        was looking at getting another top end and getting it ported also.

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

                        @Ryan-F Zeeltronic provide an array of maps that you can base yours on. They are more aggressive than the OEM maps. I've just left it as the one they provided. I altered the powervalve timings but that's about it IIRC. Best get the handheld programmer too. I found mine came with some crazy map that was totally inappropriate.

                        Always Originate, Never Pirate!

                        Ryan FR 1 Reply Last reply
                        0
                        • CalumC Calum

                          @Ryan-F Zeeltronic provide an array of maps that you can base yours on. They are more aggressive than the OEM maps. I've just left it as the one they provided. I altered the powervalve timings but that's about it IIRC. Best get the handheld programmer too. I found mine came with some crazy map that was totally inappropriate.

                          Ryan FR Offline
                          Ryan FR Offline
                          Ryan F
                          wrote on last edited by
                          #20

                          @Calum Ah ok thank you for the help, I was looking at the older CDI's but like you said alot of them look crusty and I know what you mean about the zeeltronic that is going to be my next buy 100% I don't want to make the bike crazy or nothing and i don't want mega horsepower I just like the torque and acceleration.

                          1 Reply Last reply
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                          • O Offline
                            O Offline
                            Oisin
                            wrote on last edited by
                            #21

                            Would a pinned powervalve create a loss in power and acceleration? Just wondering thanks

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

                              Depends where you pin it.

                              So it's not a clear cut answer.

                              On an unrestricted CDI a pinned powervalve would be detrimental to performance.

                              On a DTRE/X Ignition, a pinned valve will allow you to rev past 9K.
                              On a CDI where the ignition is severely retarded past 8K then it will be a loss of power all round.

                              If the CDI allows power up the higher revs, but, like the RE/X ignition, retards the powervalve, pinning it open will allow you to get that upper power, sacrificing low end.

                              It's not clear cut. For optimum performance, set it up properly and leave it alone.

                              Always Originate, Never Pirate!

                              O 1 Reply Last reply
                              1
                              • DartyD Offline
                                DartyD Offline
                                Darty
                                wrote on last edited by
                                #23

                                Just on ride ability, I feel it’s slower over all with turning the PV off essentially,

                                That’s where a good expansion pipe really helps,

                                Keep it real

                                1 Reply Last reply
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                                • CalumC Calum

                                  Depends where you pin it.

                                  So it's not a clear cut answer.

                                  On an unrestricted CDI a pinned powervalve would be detrimental to performance.

                                  On a DTRE/X Ignition, a pinned valve will allow you to rev past 9K.
                                  On a CDI where the ignition is severely retarded past 8K then it will be a loss of power all round.

                                  If the CDI allows power up the higher revs, but, like the RE/X ignition, retards the powervalve, pinning it open will allow you to get that upper power, sacrificing low end.

                                  It's not clear cut. For optimum performance, set it up properly and leave it alone.

                                  O Offline
                                  O Offline
                                  Oisin
                                  wrote on last edited by
                                  #24

                                  @Calum yea I ok and how do u tell if the cdi is restricted? I have a DT 125r 2005

                                  1 Reply Last reply
                                  0
                                  • CalumC Offline
                                    CalumC Offline
                                    Calum
                                    wrote on last edited by
                                    #25

                                    Well if the bike lacks power, that's usually a good indication that the bikes restricted. 🤣

                                    Always Originate, Never Pirate!

                                    O 1 Reply Last reply
                                    0
                                    • CalumC Calum

                                      Well if the bike lacks power, that's usually a good indication that the bikes restricted. 🤣

                                      O Offline
                                      O Offline
                                      Oisin
                                      wrote on last edited by
                                      #26

                                      @Calum haha I get yea. And how would one unrestricted it

                                      CalumC 1 Reply Last reply
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                                      • O Oisin

                                        @Calum haha I get yea. And how would one unrestricted it

                                        CalumC Offline
                                        CalumC Offline
                                        Calum
                                        wrote on last edited by Calum
                                        #27

                                        @Oisin You tried searching?

                                        https://dt125r.co.uk/topic/578/derestricting-guide

                                        Always Originate, Never Pirate!

                                        1 Reply Last reply
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