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. Derestricting
  4. Restrictions

Restrictions

Scheduled Pinned Locked Moved Derestricting
10 Posts 7 Posters 3.9k 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.
  • smudge1995S Offline
    smudge1995S Offline
    smudge1995
    wrote on last edited by
    #1

    Just wandering what restrictions are on my bike that's easy and quick to sort out I have a 2002 dtr125?
    Can anyone help.

    NINJAN 1 Reply Last reply
    0
    • ZrakoZ Offline
      ZrakoZ Offline
      Zrako
      wrote on last edited by
      #2

      https://dt125r.co.uk/category/25/derestricting

      1979 Jawa Mustang 50
      2003 Gilera DNA 125 R.I.P
      2015 Keeway TX 125 SM
      2006 Yamaha DT 125 X

      1 Reply Last reply
      1
      • smudge1995S smudge1995

        Just wandering what restrictions are on my bike that's easy and quick to sort out I have a 2002 dtr125?
        Can anyone help.

        NINJAN Offline
        NINJAN Offline
        NINJA
        wrote on last edited by
        #3

        @smudge1995 The complete guide for derestricting;

        https://www.slideshare.net/kerryprinceuk/derestricting-the-yamaha-dt125-r-1988-through-to-2007-scrimsmustangs-classic-yamaha-restorations

        SEDUCED BY THE DARK SIDE!!!

        tunertomT 1 Reply Last reply
        1
        • NINJAN NINJA

          @smudge1995 The complete guide for derestricting;

          https://www.slideshare.net/kerryprinceuk/derestricting-the-yamaha-dt125-r-1988-through-to-2007-scrimsmustangs-classic-yamaha-restorations

          tunertomT Offline
          tunertomT Offline
          tunertom
          wrote on last edited by
          #4

          @CYBER-NINJA alot of that guide is correct, but things like cutting and chopping up the inlet manifold is just bollocks, you loose power doing that, dont take this guide as gospel

          NINJAN CalumC 2 Replies Last reply
          0
          • tunertomT tunertom

            @CYBER-NINJA alot of that guide is correct, but things like cutting and chopping up the inlet manifold is just bollocks, you loose power doing that, dont take this guide as gospel

            NINJAN Offline
            NINJAN Offline
            NINJA
            wrote on last edited by
            #5

            @tunertom I take your point, my DTR had it's stock front pipe cut open and derestricted. I was unable to test for a before and after to feel the difference personally. But it's probably a safe bet that most owners will not go to that trouble and just swap the whole exhaust over for a DEP, Giannelli etc or similar after market exhaust set-up. ๐Ÿ˜‰

            SEDUCED BY THE DARK SIDE!!!

            1 Reply Last reply
            0
            • tunertomT tunertom

              @CYBER-NINJA alot of that guide is correct, but things like cutting and chopping up the inlet manifold is just bollocks, you loose power doing that, dont take this guide as gospel

              CalumC Offline
              CalumC Offline
              Calum
              wrote on last edited by
              #6

              @tunertom Yeah that inlet manifold is a load of tosh, but don't discount Scrim, he knows his shit.

              @CYBER-NINJA haha yeah I did chop my exhaust up and removed the cat, but oh my seriously those pipes have some serious weight, so if not for the performance the weight alone is worth swapping out lmao!

              Always Originate, Never Pirate!

              NINJAN C 2 Replies Last reply
              1
              • CalumC Calum

                @tunertom Yeah that inlet manifold is a load of tosh, but don't discount Scrim, he knows his shit.

                @CYBER-NINJA haha yeah I did chop my exhaust up and removed the cat, but oh my seriously those pipes have some serious weight, so if not for the performance the weight alone is worth swapping out lmao!

                NINJAN Offline
                NINJAN Offline
                NINJA
                wrote on last edited by
                #7

                @Calum Added bonus with the weight saving as well - good shout dude!!! ๐Ÿ˜‰

                SEDUCED BY THE DARK SIDE!!!

                CalumC 1 Reply Last reply
                0
                • NINJAN NINJA

                  @Calum Added bonus with the weight saving as well - good shout dude!!! ๐Ÿ˜‰

                  CalumC Offline
                  CalumC Offline
                  Calum
                  wrote on last edited by
                  #8

                  @CYBER-NINJA Weight is a restriction that affects every single aspect of performance.

                  Always Originate, Never Pirate!

                  1 Reply Last reply
                  1
                  • CalumC Calum

                    @tunertom Yeah that inlet manifold is a load of tosh, but don't discount Scrim, he knows his shit.

                    @CYBER-NINJA haha yeah I did chop my exhaust up and removed the cat, but oh my seriously those pipes have some serious weight, so if not for the performance the weight alone is worth swapping out lmao!

                    C Offline
                    C Offline
                    Carl Kennedy
                    wrote on last edited by
                    #9

                    @Calum said in Restrictions:

                    @tunertom Yeah that inlet manifold is a load of tosh, but don't discount Scrim, he knows his shit.

                    @CYBER-NINJA haha yeah I did chop my exhaust up and removed the cat, but oh my seriously those pipes have some serious weight, so if not for the performance the weight alone is worth swapping out lmao!

                    Hi I have his destruction manual and seems mostly since ๐Ÿ™‚

                    1 Reply Last reply
                    0
                    • Hark_PtooieH Offline
                      Hark_PtooieH Offline
                      Hark_Ptooie
                      wrote on last edited by Hark_Ptooie
                      #10

                      Quick answer since I have a 2002 as well (DE03):
                      1 - Swap expansion chamber (the blobby exhaust bit) to an Athena or something. This was the big thing.
                      2 - Pull out the reed switch from behind the speedometer. Do not disconnect it or cut any wires, just wrap it in tape and stuff it aside. It detects when the needle gets to ca 80 km/h and cuts ignition there.

                      That should be it, your bike should now rev freely to 9500 rpm and do 120+ km/h.

                      Also: ensure that the YPVS is working as it should. Remove the round cap on the left side and turn on ignition. It should rotate back and forth a little, then settle such that the groove on top is right over the hole.

                      Explanation on that last bit: The YPVS switches the port timing between low revs (more torque) and high revs (more power) as the revs increase and decrease. Variable valve timing, you could say.

                      When you turn on the ignition it rotates back and forth (flips between low and high mode) to scrape off soot. The resting position should be over the hole because they used that hole to fixate the valve in low-revs mode (and turning off or removing the solenoid actuating it) when they restricted bikes, but I believe they stopped using that method after 1998 or something. If it does not rotate back and forth with an audible "bzzt-bzzt" when ignition turns on, your YPVS is not working and stuck in either of the modes.

                      As for the inlet manifold I did a thorough CFD analysis and found that you cannot improve it. Leave the plastic bottle on, it smoothens out the gas flow. The carburetor should not need anything either, it is likely a Mikuni TM28SS with a 240 ยตm main jet, which is perfect.

                      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