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    • K
      Kieron12345 last edited by

      Hello I have got a Yamaha DTR 125, 1992 apparantly it says and It's in the garage at the moment getting a rebuild new speedo/thermo and whatnot and I do not have a YVPS servo or my powervalve open as it was turned off when I had gotten it and I am looking to buy a servo any ideas where I can get one for my model? I have been told by the garage that my bike could have different wiring and CDI to what my engine could be.

      1 Reply Last reply Reply Quote 0
      • A
        andrewj1680 last edited by

        I believe they didn't fit the servo before 97 unless it's a import I have a 94 and mine doesn't have a servo, your best bet is to open the power valve and pin it

        1 Reply Last reply Reply Quote 0
        • Calum
          Calum last edited by

          You could get a servo from the factory on pre 97 IF you presented Yamaha with a full bike license. Otherwise no they didn't come with one.

          Always Originate, Never Pirate!

          A 1 Reply Last reply Reply Quote 0
          • A
            andrewj1680 @Calum last edited by

            @Calum learn something new every day

            Calum 1 Reply Last reply Reply Quote 0
            • Calum
              Calum @andrewj1680 last edited by

              @andrewj1680 How many people with a license bought a brand new dt125. Pretty sure they would have just bought something bigger.

              Always Originate, Never Pirate!

              A declan 2 Replies Last reply Reply Quote 0
              • K
                Kieron12345 last edited by

                Thanks for the response I have seen loads on the internet for sale and I am wondering if I should buy it as my bike is restricted and no powervalve open and no servo and it's really slow at the moment and plus I have been told pinning the powervalve open will fuck your bike up quicker and I am getting a full engine rebuild done soon so I'll need to bed the engine in for around 500 miles, what do you guys recon?

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                • A
                  andrewj1680 @Calum last edited by

                  @Calum I know wouldn't be buying a dt125r if I had a full licence lol defeats the whole idea surely

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                  • A
                    andrewj1680 @Kieron12345 last edited by

                    @Kieron12345 I've seen it where it's fried the piston All down the front with the power valve shut too where it can't get the exhaust gasses out quick enough apparently, It's 2 stroke it's gonna go through pistons no matter how you ride it so you may aswell get the most out of it

                    Mightyman 1 Reply Last reply Reply Quote 1
                    • declan
                      declan @Calum last edited by

                      @Calum mines a 1990 with a servo does have ks on the clocks tho

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                      • Mightyman
                        Mightyman Global Moderator @andrewj1680 last edited by

                        @andrewj1680 that really doesn't seem very accurate to me...

                        TDR 125 - 2001

                        Calum A 2 Replies Last reply Reply Quote 0
                        • Calum
                          Calum @Mightyman last edited by

                          @Mightyman Frying pistons? Yeah that sounds about right to me.

                          Having the powervalve pinned open damages the engine as it puts undue stress on the bottom end.

                          You are talking about reducing its life by a fraction. As Andrew says, pistons are serviceable items on two smokes.

                          Always Originate, Never Pirate!

                          Mightyman 1 Reply Last reply Reply Quote 0
                          • A
                            andrewj1680 @Mightyman last edited by

                            @Mightyman I've seen it first hand mate it melts the front of the piston dead in line with the exhaust port, I personally pinned the power valve with the idea it's 2 stroke it's gonna want rebuilding from time to time

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                            • Mightyman
                              Mightyman Global Moderator @Calum last edited by

                              @Calum I meant when @andrewj1680 said he has seen a piston fried because the power valve was shut not letting the exhaust gasses out quick enough. @andrewj1680 are you sure it wasn't just coming into contact with the power valve? As they do need shaving down if the cylinder has been rebored.

                              TDR 125 - 2001

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                              • A
                                andrewj1680 @Mightyman last edited by andrewj1680

                                @Mightyman 0_1494937297359_Screenshot_2017-05-16-13-19-20-1.png
                                That's result of a piston hitting a power valve the cylinder melting shows the carbon buildup etc I know the difference

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                                • Calum
                                  Calum last edited by

                                  When the servo is operated there is no risk of this happening.

                                  With the servo pinned shut, yeah I could see why this would happen.

                                  Always Originate, Never Pirate!

                                  1 Reply Last reply Reply Quote -1
                                  • Mightyman
                                    Mightyman Global Moderator last edited by

                                    I must be getting the wrong end of the stick here, but are you saying that from the factory, a restricted DT (ie servo not operating) has a chance of the front of the piston melting because of the exhaust gases not getting out of the cylinder fast enough...?

                                    TDR 125 - 2001

                                    Calum 1 Reply Last reply Reply Quote 0
                                    • Calum
                                      Calum @Mightyman last edited by

                                      @Mightyman The Powervalves from the factory were pinned open, not shut.

                                      It styfuls the engine having the valve shut.

                                      The exhaust is unable to scavenge effectively and reduce the NoX gaes, as a result the engine goes into detonation, which is an engine killer.

                                      Now that's the theory, I don't know whether the DT is tuned enough to do this. But I don't doubt its possibility.

                                      Always Originate, Never Pirate!

                                      Mightyman 1 Reply Last reply Reply Quote 0
                                      • Mightyman
                                        Mightyman Global Moderator @Calum last edited by

                                        @Calum even DTREs were pinned open from factory?! I thought they were restricted to conform to the 15bhp limit of younger riders? Surely pinned open they would have the full power at higher revs?

                                        TDR 125 - 2001

                                        Calum 1 Reply Last reply Reply Quote 0
                                        • Calum
                                          Calum @Mightyman last edited by Calum

                                          @Mightyman Nah the DTRE's were given full YPVS servos.

                                          Although you make a good point, the YPVS does shut off at 10'000 rpm as a restriction.

                                          But the point here is the build up of NoX's gases. So whilst they did shut off, the normal person would be part throttle anyway. And if you were pinning it, well you would expect it to give up eventually and this might be why.

                                          Always Originate, Never Pirate!

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