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Technical Zone

1.3k Topics 11.5k Posts

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  • Suspension Related

    100 768
    100 Topics
    768 Posts
    HOTSHOT IIIH
    @reudtr88 The seller is right, the spacers and caliper bracket are narrower than the DT125R versions. The bench mock-up in the pics above comprised a 3ET DT200R swingarm, caliper hanger and spacers mated to a DT125R hub. As you can see the 428 sprockets lined up quite well (I also had to use a 3mm thick M20 washer between the caliper hanger and swingarm to get it as good as it could possibly be with the items I had to hand).

  • Exhaust Related

    65 575
    65 Topics
    575 Posts
    CalumC
    @hensmaxim Just contact him directly via Facebook or something, he did my pipe for me silly cheap.

  • Framework Related

    86 606
    86 Topics
    606 Posts
    CalumC
    That's normal. All DTs are like that. [image: IMG-20251011-114625.jpg]

  • Wheel Related

    83 749
    83 Topics
    749 Posts
    R
    Just measure from the inside of the fork leg to the rim on each side, +-2mm should be ok I think. If you release the nuts on the axle clamp on the right side (if I remember correctly) and pump the front suspension up and down, and then re-tighten, it should not bind. If the seals wear out too quickly, I would check the surface of the fork tubes, so they are not damaged (pitted from rust, flaking chrome etc.)

  • Electric Related

    269 2k
    269 Topics
    2k Posts
    CalumC
    What specifically do you mean by cut? The Tachometer is mechanically driven on the DTR. So you need to replace the tachmeter cable back into the gearbox and the clocks. If you mean the lights etc, then there are many wiring diagrams already uploaded to this forum. Workshop manual is pinned: https://training.dt125r.co.uk/files/Yamaha_DT125_Workshop_Manual.pdf [image: 52172141696_84e3b69382_b.jpg]

  • Brake Related

    70 459
    70 Topics
    459 Posts
    CalumC
    Do you mean dual piston caliper? Or do you want two calipers 🤭 https://ebay.io/m/yOnXyn Or have one made using Nevs design [image: 27961158925_26ab4db984_c.jpg] https://dt125r.co.uk/topic/1343/dt125-front-brake-caliper-bracket-dimensions/2?_=1772783708212

  • Engine Related

    552 5k
    552 Topics
    5k Posts
    P
    @Carl-Kennedy hello, I had the same problem. Found out that someone ripped out the mechanical gears out of it, you can try that. And if you happenned to have them, could you please tell me the dimentions of the gears? Thanks
  • F

    forks

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    11 Posts
    3k Views
    F
    @calum pulled it out to get a pic ended up pulling legs to see what crack is, dtx stanchions are shorter, the insides are slightly different too ive added a shim/washer ontop of the springs seems to have lifted it abit but still not quite there, not sure how to upload a pic as it says its too big of file
  • rking7888R

    Yz mudguards

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    0 Votes
    3 Posts
    2k Views
    NottsbikerN
    Fit fine on the 125 only need drilling if UFO or Acerbis etc Put one on my DT200WR but had to cut the back of it down as it hit the rads
  • C

    DT125 R(4BL) Parts no longer available (new)

    1
    0 Votes
    1 Posts
    965 Views
    No one has replied
  • G

    Tacho reading 1500 when engine not running

    3
    0 Votes
    3 Posts
    803 Views
    G
    Hi, okay, thanks @declan - may try and get it open , knowing there will be a backup plan!
  • B

    Dt 125re No power.

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    0 Votes
    4 Posts
    1k Views
    declanD
    @Baileyboy2008 well like Calum pointed out there’s no such thing as pinning your valve half way if the valve is have way closed you will get zero power above 6k open her all the way and then see what it does
  • DartyD

    The Library

    dt125r dt200wr wr200
    5
    5 Votes
    5 Posts
    2k Views
    NottsbikerN
    Yes very rare now and you have to hunt high and low to find anything at sensible prices I'm afraid
  • D

    Dtr 125 pressurizing problem!

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    0 Votes
    9 Posts
    2k Views
    CalumC
    Pressure Cap! I wouldn't believe it but I have seen it a few times. Always start off with something cheap and look at the more expensive items later.
  • Ryan FR

    Bike lacks power

    27
    0 Votes
    27 Posts
    6k Views
    CalumC
    @Oisin You tried searching? https://dt125r.co.uk/topic/578/derestricting-guide
  • B

    Still no spark on my DT125RE

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    0 Votes
    9 Posts
    1k Views
    CalumC
    Measure across the pick up sensor. Make sure that you are getting current to trigger the CDI. You will want to follow that pulse from the pickup to the CDI. From the CDI you will see it go to the primary coil. From there it should go to the secondary mutal winding and out to the HT lead. It's as simple as that. Somewhere you are losing that signal.
  • riley_racerR

    Stickers/Decals

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    0 Votes
    14 Posts
    2k Views
    riley_racerR
    @oldman just had a quick search, looks ideal, cheers mate
  • V

    Why does it do this?

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    7 Posts
    1k Views
    V
    @markus-w thanks
  • V

    Should theese jets fit my yamaha dt 125 x 2006 witk mikuni tm28-92 carb (stock carb)

    1
    0 Votes
    1 Posts
    543 Views
    No one has replied
  • J

    Dt125re 2004 servo

    servo
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    0 Votes
    11 Posts
    2k Views
    C
    so @Jgb19830 did you fixed it,just by that? i have the same problem.
  • 2

    This sounds like bottom end bearings right?

    4
    0 Votes
    4 Posts
    748 Views
    CalumC
    Well you should have checked the bearings at the same time. For up or down play.
  • W

    HID headlight conversion

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    0 Votes
    6 Posts
    1k Views
    N
    @ward4014 Just fit some brighter bulbs for a super easy and cheap upgrade; https://www.ebay.co.uk/itm/2-x-H5-P45t-Birnen-Halogen-Auto-Lampen-6000K-60-55W-Xenon-Weis-12V/362660604593?hash=item547041aab1:g:GEkAAOSw~dJdNZD9
  • W

    New piston but no rebore

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    4 Posts
    1k Views
    W
    Thanks guys I'll take it to the shop once I have it off I'm only changing the piston because I have never changed it it rides mint but just peace of mind
  • W

    Reset milage to 0

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    0 Votes
    4 Posts
    843 Views
    CalumC
    My aftermarket clocks reset to zero. Now my mot history is all over the place. I don't intend on selling the bike so makes no odds to me. Would be nice to see how many miles I have done in ten years though.
  • P

    General maintenance

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    CalumC
    @panmil92 I don't recall there being any certain type of weak point. Fairly bullet proof motors. It's just general items. Bearings, bushes and seals.
  • J

    Piston play

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    0 Votes
    2 Posts
    645 Views
    J
    https://youtu.be/p5XOQFRJzko Here it is running... Story is it overheated on a ride out due to an airlock in the cooling system. So the piston went pop
  • S

    2007 dt re blue frame colour code??

    3
    1 Votes
    3 Posts
    1k Views
    declanD
    @Minia I believe it’s on the frame tube under the rear of the mudguard