'02 DT125R Rebuild



  • Hi folks,

    Welcome one, welcome all, to the rebuild of my 2002 DT125R. Got the bike back in 2011 and rode it for a year or thereabouts. It was noticed that the engine oil was looking very creamy, the colour of Bailey's liqueur - a water leak was suspected and given that the radiator had required constant filling over the time I rode the bike this made sense. By this point I had just passed my test and a new bigger bike was already parked in the garage alongside the DT. And thus she was consigned to a dark corner of the garage.

    In that time I moved a-ways away and had many different bikes since then. Financial circumstance has seen them all go however and now the DT has been summoned into action once more. This week after a 7 year hiatus in storage she has finally arrived back to me and the restoration begins.

    So here are the objectives for the build:

    1. Repair and have the bike running again
    2. MOT and roadworthy
    3. Bolt/Parts replacement

    -- This finish line is to have the bike as my daily vehicle and in an aesthetically acceptable condition. Having achieved this Ill be in a position to consider maybe doing a complete 100% restoration in the future.

    Heres how it was found, beneath a garage full of nonsense and half tucked in a wardrobe:
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    And a few more pics once dug out:
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    On the surface it seems OK, in need of a damn good clean. I started the teardown today and...its turned out to be something of a little shop of horrors. Will endeavor to get more pictures taken of individual components just not in the habit of remembering to take snaps yet.

    Less pretty:
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    By the close of play today I managed to get further than these pictures and have the bike down to a rolling chassis with just shock, engine and swingarm being the major components to drop out next. The frame was painted years ago with hammerite and looks like balls. There numerous corrosion spots all over too. The bolts used on this bike are mix and match specials from previous owners and bodges from me. Most are destroyed at this point and need replacing. The radiator mount was actually held on with cable ties and a single bolt. By far the worst discovery was the cooling system, which was actually still filled with water. Just water mind you - pretty sure it was old tap water and no anti freeze. See what came out of the radiator below:

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    Major concerns currently in getting out two snapped bolts from the engine - one is part of the mount which the boost bottle clips on to (unsure of the name). Another is on the exhaust header (held on by a single bolt). The pivot on the swingarm also seems to be jammed solid - it'll spin but not had luck getting it to move out yet. Will be taking a big hammer to it soon. I had originally been optimistic that hopefully things would be better than expected, but the externals have me fearing just how bad the engine internals are going to be once I get it out. Should also mention its looks like my YPVS(?) pulley on the left hand-side is damaged - Cable "2" is snapped at the adjuster but still connected.

    I havnt been as organised as usual with his teardown in assigning bolts and bits to respective containers etc. At this time Im likely to buy a large box of bolts and just do a total bolt restoration anyway so little reason to keep the old rubbish. Stopping the perfectionism is the tough part, where does the replacing of parts end!? I also intend to spend a lot of time with the wiring loom and have it properly tidied and in good order. To that effect I have invested in some crimpers, solder and proper shrink wrap. Will be studying the wiring diagram at bedtime for next few weeks.

    All of these are challenges that can be overcome however, with the trusty haynes and no doubt the infinite wisdom of the forum. Will hopefully have some more updates for you all soon and a bit more detail on the task list ahead.

    As preliminary questions for you all:

    • The engine rebuild, better to buy the parts (and which parts?) or send to PJME/whoever to do?
    • Worth getting the frame powdercoated or just bodge the corrosion for now and wait till the full resto?

    Thank you all for reading, stay tuned for future - more organised/coherent - posts.



  • If you've got the time it's well worth getting the frame powdercoated, especially if you intend on using the bike extensively and want it last. Done properly a proper powdercoat should last 20 years. I'd have it shot blasted and powdercoated.

    Engine wise, easy enough to do yourself, just get the crank rebuilt by a specialist.