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DT125R FORUM

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  4. New purchase 1990 dt125r

New purchase 1990 dt125r

Scheduled Pinned Locked Moved Welcome New Owners!
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  • O oldman

    Here's one I prepared earlier !
    0_1502570553952_20170715_131805.jpg

    U Offline
    U Offline
    ukchad
    wrote on last edited by
    #22

    @oldman soooo clean

    1 Reply Last reply
    0
    • U ukchad

      Is it normal for the exhaust to heat up so much then, when the power valve is fully open?

      Also died a bit when I kicked up into 6th, ran out of power (maybe wasn't high enough revs)

      declanD Offline
      declanD Offline
      declan
      wrote on last edited by
      #23

      @ukchad coming from 4 stroke this was crazy for me I have full functioning pv) my muffler gets too hot to touch

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      0
      • terry.tzT terry.tz

        @declan coming on that is Declan

        declanD Offline
        declanD Offline
        declan
        wrote on last edited by
        #24

        @terry-tz hey thank you buddy nice hearing that much appreciated but a lot to go yet 😊

        terry.tzT 1 Reply Last reply
        0
        • declanD declan

          @terry-tz hey thank you buddy nice hearing that much appreciated but a lot to go yet 😊

          terry.tzT Offline
          terry.tzT Offline
          terry.tz
          wrote on last edited by
          #25

          @declan good to know there's more to come

          "Muddy water is best cleared by leaving it alone" Alan Watts

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          0
          • CalumC Online
            CalumC Online
            Calum
            wrote on last edited by
            #26

            Hello and welcome'

            Get the servo retro fitted and have a working powervalve. Best of both worlds.

            Exhaust gets hotter because you spend longer times at higher rpms. Refer back to my previous statement. Get the servo fitted. Less stress on the engine.

            I would start simple first, check the thermostat, they are probe to failing after zo many years.

            Head gasket is not the same as a four stroke. No valves no nothing to go wrong.

            Buy only genuine or athena gasket, skim the head like described in my tutorial, then boom, good to go.

            Nice bike.

            Always Originate, Never Pirate!

            declanD U 2 Replies Last reply
            0
            • MiniaM Offline
              MiniaM Offline
              Minia
              wrote on last edited by
              #27

              Welcome, looking good 🙂

              Yamaha DT125R Blue 2002, XT 125 1982, Yamaha WR250Z 1992, BMW GS650F 1994, Benelli BN302 2015

              1 Reply Last reply
              0
              • CalumC Calum

                Hello and welcome'

                Get the servo retro fitted and have a working powervalve. Best of both worlds.

                Exhaust gets hotter because you spend longer times at higher rpms. Refer back to my previous statement. Get the servo fitted. Less stress on the engine.

                I would start simple first, check the thermostat, they are probe to failing after zo many years.

                Head gasket is not the same as a four stroke. No valves no nothing to go wrong.

                Buy only genuine or athena gasket, skim the head like described in my tutorial, then boom, good to go.

                Nice bike.

                declanD Offline
                declanD Offline
                declan
                wrote on last edited by
                #28

                @calum what's skimming the head do I know squish and compression etc but does just that on its own yield noticeable results?

                1 Reply Last reply
                0
                • U ukchad

                  Hello everyone,
                  Just brought myself a DT125R.
                  Always wanted one since I was knocking around at 15 on my CB125 - finally got the cash to treat myself.

                  Found on EBay
                  UK registered from new, engine and frame numbers match.

                  Bit scruffy, but perfect for me to fiddle around with at the weekends

                  0_1502565963724_IMG_2819.JPG

                  Not sure if I loaded the photo properly!

                  Plenty of tidying to be done on the bike, electrics, decals, plastics, tank etc etc, but looking forward to it and coming here for advice!

                  NINJAN Offline
                  NINJAN Offline
                  NINJA
                  wrote on last edited by
                  #29

                  @ukchad Welcome aboard, looks like you have a decent starting point there. 👍

                  SEDUCED BY THE DARK SIDE!!!

                  1 Reply Last reply
                  0
                  • CalumC Calum

                    Hello and welcome'

                    Get the servo retro fitted and have a working powervalve. Best of both worlds.

                    Exhaust gets hotter because you spend longer times at higher rpms. Refer back to my previous statement. Get the servo fitted. Less stress on the engine.

                    I would start simple first, check the thermostat, they are probe to failing after zo many years.

                    Head gasket is not the same as a four stroke. No valves no nothing to go wrong.

                    Buy only genuine or athena gasket, skim the head like described in my tutorial, then boom, good to go.

                    Nice bike.

                    U Offline
                    U Offline
                    ukchad
                    wrote on last edited by
                    #30

                    @calum so I think I understand.

                    At the moment the power valve either works at low down or higher revs because it is fixed in position?
                    I choose that position by turning 180 degrees either way?
                    By fitting a servo, the power valve is rotated to give me full power depending on revs.
                    Is this correct?

                    My power valve doesn't look like most i see in pictures - no cables or slots for cables in the casing. Just a central bolt, flanked by 2 small outer bolts

                    Can a servo still be retro fitted to this?

                    1 Reply Last reply
                    1
                    • NottsbikerN Offline
                      NottsbikerN Offline
                      Nottsbiker
                      wrote on last edited by
                      #31

                      Yes you are missing the cables, servo, cable housing, cover and pulley.

                      You can get these from any DTR or TDR and they will fit your bike. Not sure on servo motor but i think any DT one can be adapted to fit

                      1 Reply Last reply
                      0
                      • U Offline
                        U Offline
                        ukchad
                        wrote on last edited by
                        #32

                        Thanks @Nottsbiker

                        If any one knows, finds or has one that fits please bear me in mind.

                        I can then start a build thread and you can all watch me mess it up!

                        1 Reply Last reply
                        0
                        • NottsbikerN Offline
                          NottsbikerN Offline
                          Nottsbiker
                          wrote on last edited by
                          #33

                          Think you and i will be after m the same vintage servo motors 😉

                          Don't out bid me on any lol

                          1 Reply Last reply
                          0
                          • U Offline
                            U Offline
                            ukchad
                            wrote on last edited by
                            #34

                            Let me know, and we can make sure!

                            1 Reply Last reply
                            0
                            • A Offline
                              A Offline
                              andrewj1680
                              wrote on last edited by
                              #35

                              The powervalve is different you would have to change the whole lot in my opinion its not worth it the servo takes the fun out of it anyway

                              declanD 1 Reply Last reply
                              0
                              • A andrewj1680

                                The powervalve is different you would have to change the whole lot in my opinion its not worth it the servo takes the fun out of it anyway

                                declanD Offline
                                declanD Offline
                                declan
                                wrote on last edited by
                                #36

                                @andrewj1680 0_1502635173746_IMG_1500.JPG

                                Any idea what that yellow and black wire does that goes to the powervalve servo it turns using the key still?

                                1 Reply Last reply
                                0
                                • A Offline
                                  A Offline
                                  andrewj1680
                                  wrote on last edited by
                                  #37

                                  At a guess mate that 1 sends signal from the cdi unit, have you tried riding the bike to see if it still cuts in?

                                  declanD 2 Replies Last reply
                                  0
                                  • A andrewj1680

                                    At a guess mate that 1 sends signal from the cdi unit, have you tried riding the bike to see if it still cuts in?

                                    declanD Offline
                                    declanD Offline
                                    declan
                                    wrote on last edited by
                                    #38

                                    @andrewj1680 on it right now and no decent seem to be and it always lands on the open position crazy how much different the bike sounds when it's open

                                    1 Reply Last reply
                                    1
                                    • A andrewj1680

                                      At a guess mate that 1 sends signal from the cdi unit, have you tried riding the bike to see if it still cuts in?

                                      declanD Offline
                                      declanD Offline
                                      declan
                                      wrote on last edited by declan
                                      #39

                                      @andrewj1680 love it it's actually use able at low speed now but my idle has gone up to 2.5 when I'm gear in neutral it drops back down to a slow 1.5 any reason for this?

                                      1 Reply Last reply
                                      0
                                      • A Offline
                                        A Offline
                                        andrewj1680
                                        wrote on last edited by
                                        #40

                                        I dont know about that 1 mate but see what i mean about them being more fun, my dt i use most just to thrash about has now covered 1100 miles with the pv pinned and it hasn't been a problem at all

                                        declanD 1 Reply Last reply
                                        0
                                        • A andrewj1680

                                          I dont know about that 1 mate but see what i mean about them being more fun, my dt i use most just to thrash about has now covered 1100 miles with the pv pinned and it hasn't been a problem at all

                                          declanD Offline
                                          declanD Offline
                                          declan
                                          wrote on last edited by
                                          #41

                                          @andrewj1680 yes I do I haven't ridden it properly only on my garden but I could ride smooth at low speeds with the pv it was way choppy and was un usable for me in 1st

                                          1 Reply Last reply
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