Derestricting a 2002 DT125R

  • Sorry about this but I can't find the black and green wire, but a bit of a catch up to where I am.

    Full dep system
    Zeel CDI

    On the Speedo loom i have 4 wires on both sides of the connector block, two of which go to the instrument light the other two to the reed.

    Any suggestions would be great


  • If yours has got the reed switch in the speedo it wont have the black/green wire. Pretty sure fitting the zeel would do away with that restriction anyway.

  • Hi mate.
    I'm a biker for over 35 years, I've owned a 2002 UK spec DT125R since 2004 (I love it more than my Suzuki GSX-R 750K2 and my Kawasaki KH 250 with a 350cc cylinder swap).

    My bike is absolutely stock, two owners from new, low mileage. And it derestricted itself.... with a bit of help.

    I've actually had it on a dyno and at the back wheel it's producing 17.25 bhp.
    It revs out in top, and the speedo needle hits the stop at 80mph. I didn't trust the speedo so I used a GPS app to verify the top speed. Turns out it was a genuine 82mph.
    Which is fast enough.

    The dyno people checked the emissions, because I wasn't sure how safe it was to frap it, and on a standard airbox/carb/exhaust set up, it's safely rich, so you don't need to worry.

    All that I've done is

    1. Use fully synthetic Castrol two stroke oil
    2. Warm engine well before thrashing
    3. Move the reed switch (and wrap in a little plastic bag to protect it). DO NOT CUT THE WIRES!!
    4. Shook the expansion chamber part of the exhaust, and sure enough I heard the rattle of a detached restrictor washer... I didn't have to cut it open or anything.

    That's it.
    No DEP, no high flow filter (apparently the airbox is identical to the 200cc version so it's plenty big enough for your 125), no rejetting.

    I've read in Practical Classics that a well set up Zeeltronic system will get you safely up to 19.5bhp... but finding a place that sells it, and booking dyno time is a pain.

    Just for your information. On standard gearing, each 1,000 rpm equals a genuine 8mph in 6th.
    So despite what your speedo may say, 8K rpm is a genuine 64mph.

    Good luck.

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  • @Anditover You need to wait until the image populates the preview box before clicking submit. Otherwise it's just text you are responding with, as shown in your response dude. 😉

  • @Anditover Loads of places sell the Zeeltronic. And it will come with 5 or so maps so you don't need a Dyno.

    As I've said time and time again, it's not all about peak power with the zeeltronic, but the overall power made. You will find it pulls a lot better with a zeel than stock ignition.

    It's a worthwhile investment, but I'm not sure it's what you would really be after considering the bikes you've got.

  • Thanks all, I'm only asking as I'm interested, the bike came with a DEP system and the wiring was butchered hence the Zeel CDI. I'm building it for a mate, I'm more into classic Brits.