Kit 200CC to upgrade the Yamaha dtr 125



  • Kit 200CC to upgrade the Yamaha dtr 125. Has a 66,7 x 57mm bore and stroke and
    uses a crankshaft from a Yamaha blaster quad so needs the dt cases machined to
    allow for the larger crankshaft web.
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  • The blaster crank means you'll have to reduce spacer thickness behind primary drive gear and loose 30% meshing with the clutch teeth. I originally used a blaster crank in my 200cc project but replaced with a wr200 crank (with my wr200 top end) also if I remember correctly the blash has 0.8mm shorter stroke.

    Nice looking kit. Any more information?



  • @Louis-James hi yes was aware of that so going to use some steel rod the same diameter as the shaft and and drill and tap to 11mm thread. Then cut the keyway in to match the shaft.
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  • Good thing removing the washer behind the crank nut gives an extra 5mm from memory. What cylinder, head and powervalve are you using?

    Also from memory the flywheel sides tapered seat fits fine with the 03 DTR flywheel but didn't fit an electric start flywheel that I tried on. I also ran a "stepped Woodruff" key to advance the timing before I had the zeeltronic CDI made for the dt125r (didn't exist at the time) ran absolutely fine with the blaster crank but no where near as much torque as now with the zeeltronic



  • Hi @Louis-James parts are going on an 03 dtr and already fitted a 4 degree advanced woodruff key i made. The cylinder, head and powervalve have all just been custom made by BAracing in Portugal and all the porting a lot higher spec than an old 3xp cylinder for example. They build a lot of quick bikes with lots trophies for 1/4 mile records etc, they build a dt 100cc that will do 186kph and power wheelie in every gear.
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  • @2stroketerry what was the cylinder originally? 3xp? Does the head have frame mount? I'd be interested in a spare head for my spare brand new 3xp cylinder (nickasil)
    Very nice stuff 😎



  • @2stroketerry said in Kit 200CC to upgrade the Yamaha dtr 125:

    Hi @Louis-James parts are going on an 03 dtr and already fitted a 4 degree advanced woodruff key i made. The cylinder, head and powervalve have all just been custom made by BAracing in Portugal and all the porting a lot higher spec than an old 3xp cylinder for example. They build a lot of quick bikes with lots trophies for 1/4 mile records etc, they build a dt 100cc that will do 186kph and power wheelie in every gear.
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    I have one of these spare somewhere from before



  • Here is BAracing testing an Athena 170 they just built.
    https://www.facebook.com/TeamBARacing/videos/990810477764205/
    A friend had a spare 3xp head a while ago will see if still has it for you



  • Are you running a supermoto?
    I find my 200 scary as the front wheel is hard to Keep down in 1-3 gears.
    Any more pictures of your project? What carb will you run?



  • Yeah fair play, those lads over in Portgual know their stuff.



  • Interested in doing a similar thing with the woodruff key on my 125 bore Dt, wonder how big the affects of 4 degree advance are? Much loss in engine life also?



  • @glynn123 It's advancing the whole ignition system which is less than ideal. Increasing the risk of detonation and pointless if you just get an aftermarket ignition system since you can alter the spark electronically.