Project I can't leave things alone!

  • Hi all so here we go.... my 2000 dt125r

    i've had the bike since 2008 and it love it.

    a picture from my last overhual in 2012


    some pictures of me having fun the day she got her mot after the last over haul.




    I've really loved this bike and i took good care of it. i was riding it up until feb 13 when i got my car licence and then it sat.

    during this time i managed to find a yz125 engine that i thought would be great so i sold my 3mb fully running engine to a friend for £150!!!!! DOH looking at the prices of them on ebay now i feel a bit stupid.


  • So here we go once again i'm rebuilding the bike 🙂

    this is where the project starts:


    i have already made a start and thanks to @Calum 's bearing cup guide i have started making the yz125 forks fit my dtr.





    so lets talk forks..

    i had the bearing cup made up at a local machine shop using Calum's design. i took the design down with the frame and the yokes. the measurements had to be adjusted to make the cup fit the frame as the size wasn't correct for my frame. i'm not saying his design and measurements was wrong in anyway it just wasn't quite right for my frame. unsure if it changes throughout the models slightly.

    so as the yz125 stem is longer and the stock yz top bearing is large than the dt frame the bearing cup is required to make it all fit.

    i used a stock yz125 top bearing and stock dt125r bottom bearing to make it all fit. no modifications are required to make the dt bearing fit the stem it's the correct size believe it or not and theres no play.

    the axle spindle is larger on the yz forks so you will need to use the yz front wheel.


  • Oh yeah i forgot to say i'm mocking the bike up fully to check fitment of stuff before it's stripped down and sent for powder-coat.

    so the yz front wheel turned up yesterday -



    so WOW it's already starting to look good! the wheel came with the stickers ETC so i will be sorting that out and putting it back to stock.

    next question on my mind is how to get the vapor digital clocks to fit the yokes as they have no mounting points like the dt. any suggestions @Calum ?

    Engines -

    so i have two engines to choose from

    left engine - 1986 yz125 1lx

    brand new wossner forged piston
    complete bottom end rebuild every bearing replaced etc
    new kick start spindle
    new clutch
    new gear selector spindle
    new water pump
    brand new mikuni carb 38mm. (tape on top is keeping important throttle cable screws with it)

    right engine 1998 yz125 4ss
    bought off of ebay looks ok and feels good on the kick start but other than that who knows. i haven't even run it.



  • Administrator

    Looking good.

    I went for wr400 forks. But there was a place for a number board which I mounted it to.

  • Global Moderator

    My vapor clocks came with a set of mounts that allowed you to put it into any normal sized set of handle bars so if you mention you'll be fitting it to a yz 125-ish bike, they may give you the same mounts.

  • @gareth_iowc Sweeeeet. Dream project, those 86/87' YZ125 engines are a funny engine, think they were rated at 24hp?

    You could expect to see 9-10 more HP and substantial torque with your 98' engine.

    What are the dimensions for your bearing cup? Alot of people looking at fork upgrades

  • Administrator

    @Darty My sketches should be uploaded here. But then they were for a probably odd forks

  • Evening all,

    Follow @Calum guide -

    I don't know the measurements off hand as the machine guy did it. It was dam close was only a millimetre or so out..... well that's what he told me.

    Calum's guide is great just take that with your yz forks, new yz top bearing, new dt bottom bearing and the frame to a local machine shop and they should work some magic no problems at all.

    One interesting think was the stops on the yz are on front centre of the fame and the dt has two rear ones. Luckily it gives the correct steering angles with no modification 😆 Winner.

    Little update today the yz 125 rear swing arm turned up today. Would have been great but it doesn't fit.
    I was surprised to find it's not as wide as the original dt one at the frame. It was only cheap and I didn't think it would fit with out some modifications but as it's smaller I'm going to scrap that idea.

    I would like the dt200 one was it Calum? But I can't find one for sale in the uk and for a good price.

  • @Darty yeah I'm going to use the 98 as it's closer to the bikes year. Started it finally today as well sounded great. Ears are still ringing.

    The 1lx will be up for sale with 0 running hours fresh rebuild. I thought that was 33bhp as well? I'll have to have another look on the net.

  • @gareth_iowc Is the YZ engine a straight swap with no or minor mods required then???

  • Yeah fits but needs a few modifications. Needs custom head to frame brackets and the front engine brackets.

    The decider was the fitment between the swingarm and that fits no modifications 😃

  • So the yz rear wheel turn up today 😃

    It's 19 inch rather than the stock 18 inch dt wheel.

    Looks like it's going to work great only thing I've noticed so far is the yz spindle is larger than the dt.
    The calliper carry will need a little adjustment to make the new spindle fit.




  • @gareth_iowc Nice fat rubber you have their bud - looking good so far!!! 👍

  • 0_1489608758997_IMG_5078.JPG

    Got the new bolt for the dog bone to mount it to the frame from fowlers 🙂

    Just waiting for the rear axle spindle to turn up so I can get the rear wheel fitted 🙂

  • 0_1489776010911_IMG_5105.JPG

    Doh!! So the yz spindle is a lot shorter than the dt. So the next thing to try will be to see if I can take the dt wheel hub and fit it in the yz wheel with the yz spokes.


  • @gareth_iowc This dude runs a wheel rebuilding service and has a good rep;

  • Thanks 🙂 only problem is I don't have Facebook lol.

    Might try a local bike shop as I've been told it's quite involved with getting it right.

  • @gareth_iowc No Facebook??? Dude your missing out. There are some wheel builders on ebay too.

  • Administrator

    @gareth_iowc Yeah wheel building is a dark art, so I am told.

  • Haven't posted in a while but things are still slowly moving .


    The wheel has been with the builder for a week now so hoping to have it back soon.

    Ordered the wrong front yz calliper doh!! So sending that back and ordering another. They calliper carry is wider on a 98 then the 97. My forks are 98 🙃.

    The yz exhaust has arrived as well but I forgot to take a photo. It doesn't quite fit might need a little bit of heat and some bending to make it work but it's not to far off.


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