Dt125r slow after rebuild



  • Hi all I got my 2002 yamaha dt125r and it had low compression but was fast still did 70-80 I had it rebuilt because of low compression and now it's slow and only does 60 pinned in 6this gear I can feel the powervalve when I accelerate it just doesn't get to the speed it used to and comments are appreciated



  • Thread moved as this isn't a project thread. It's also nice to throw an introductory thread uo in the general discussion area to introduce yourself before asking questions just as a way of common courtesy.

    It's a two stroke, compression shouldn't really be an indicator unless it's really failing to generate psi's. Compression tests are generally used to compare cylinder to cylinder and to ensure consistency across all cylinders.

    Sounds like you know what the problem is. Powervalve. Either installed the wrong way round or nkt setup.

    Best way to check is lock it in the open position and take it for a blast. Shohld have zero bottom end. Rev right through the rev range and pull strong.

    That is a good indication of what the problen isn't.



  • I had a garage look at the powervalve today it goes to the 2 when idling and when revving it goes to the middle position in line with the hole and when about 6k it goes past the hole and to the 1 position I'm not sure if that's right but they said it was how do I pin it in place so I can try ?



  • @micheal-cox I have not found that the powervalve works properly in neutral.

    Best thing is to take the exhaust off and manually set it and disconnect it from the servo.