Bought DT125X, cannot get it to start? Spark, fuel OK



  • @Lorant2 See here for more info which may help you out;

    http://www.ngksparkplugs.co.za/technical/technical-spark-plugs/



  • Yeah common problem. Powervalve needs to be modified at that overbore size.



  • I just have contacted the local Yamaha official service by email. The bike was indeed serviced at them. But they only did the top end, I guess the bottom was made before that. They told me that a prox piston was installed, even though they only charged the previous owner like 70 euros for it which doesnt even cover the prox piston price, so I guess thwy just installed this 20 euro RAM piston. It is a mess that they just went over the fact that the power valve was definately hitting the piston.



  • Definitely should have known to modify the valve, that's a well know thing on YPVS engines.



  • @Lorant2 Sounds like a right bodge job! Sadly it seems that you will have to sort their mess out.



  • I believe they mostly do 4 stroke engines nowadays in a yamaha workshop, it was maybe too easy for them lol 😃
    I am doing my best to bring this bike back to life, and planning to keep it for a few years as I wont be having more money for a newer one in a while.
    The piston is arriving tomorrow, I will make a video of the bike running if I manage to assemble it in the weekend. Main and Pilot jet arrived today 😃



  • @Lorant2 At least you will have peace of mind once it's fixed properly and some bike history as well too. 😉



  • Managed to start it, has a nice engine and exhaust aaand airfilter sound 😃

    It is running smoothly so jetting is almost correct and needle position too, also starts if I just tap the starter button even without applying throttle. Only problem is it smoking if I apply full throttle, so I will have to adjust the air filter as it was cut open but a plate was glued back with 4 small holes, it has a mesh on the top of it for a little filter effect so I will just drill more holes later, also my plug is dark brown, needs more air.

    I painted the resonator, and applied some exhaust gasket on the cylinder connection so it is not leaking, but it is missing the silencer rubber and the pipe that is part of the stock silencer was torn off at the welding so I will have my father to reweld it for me, then I paint that too.

    Also applied some 10W universal indicators to rear because someone replaced them with 21W and the hazard switch wasn't working that way.

    Engine sound
    Startup like a boss



  • @Lorant2 Sounds good bro, it looks like you are back on track for some summer fun!!! 😎 😎 😎



  • @NINJA Thanks, I have to get the A1 licence now 😂 But the summer will be definitely fun! 😉


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