Yamaha DT 125 DERESTRICTING
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I removed the exhaust and the piston looks like this...
https://i.postimg.cc/Bj4tBnD6/adw.jpg
https://i.postimg.cc/xcrXqR1L/daw.jpg
https://i.postimg.cc/ykFkRZDt/daws.jpgBtw is YVPS set good? Is it supposed to look like that in the cylinder?
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I removed the exhaust and the piston looks like this...
https://i.postimg.cc/Bj4tBnD6/adw.jpg
https://i.postimg.cc/xcrXqR1L/daw.jpg
https://i.postimg.cc/ykFkRZDt/daws.jpgBtw is YVPS set good? Is it supposed to look like that in the cylinder?
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@Lukas55 looks like the ypvs can be set better did you have proof that the piston was changed
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@declan
No ... Very stupid mistake, Next time I'll take off the exhaust to check ...Never can't trust people I guess. -
All you’re gonna have to do is undo the pulley bolt and rotate the power valve till it’s ‘smooth’ with the exhaust port and refit the pulley. It should cycle closed then open when you turn on the ignition. It should only close again when you run the engine...
Should take you 30 mins, then enjoy!!
P.S. there’s a good chance that you will have to adjust the cables as well. Just make sure that the power valve is at the open/smooth position, that the pulley pointer/thing is set towards the little 3mm hole and adjust to fit..
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By the way you have the power valve set I’m guessing you don’t really get past 7000 rpm in any gear?...
I have an early Dtr like yours. I also have a working power valve servo fitted. Finding out information on how to properly fit it was nearly impossible. I had to watch videos of 3wire servos starting up on ignition then running. I don’t know about later 5wire servos, but your power valve needs to be set in the ‘pinned open’ position when the engine isn’t running. The way it is set at the moment it is restricted and the servo will only try to close it more. It’s a wonder that it runs any sense at all the way it’s set...
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By the way you have the power valve set I’m guessing you don’t really get past 7000 rpm in any gear?...
I have an early Dtr like yours. I also have a working power valve servo fitted. Finding out information on how to properly fit it was nearly impossible. I had to watch videos of 3wire servos starting up on ignition then running. I don’t know about later 5wire servos, but your power valve needs to be set in the ‘pinned open’ position when the engine isn’t running. The way it is set at the moment it is restricted and the servo will only try to close it more. It’s a wonder that it runs any sense at all the way it’s set...
@SpookDog That's how I usually set my valve.
I've never encountered problems aligning the valve.
Going from a completely broken setup to work.
Turn ignition on and off. This is how the powervalve should be when it is fully open.
So it is just a case of adjusting the cables so that the valve is flush with the exhaust port. In some instances people have put the cables around the wrong way so that it is not operating correctly. But that's easily rectified.
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Yeah, the cables are clearly numbered 1 & 2. In my case they didn’t match up. I had to cut some outer off of one as well, to make it fit and work.
unbelievable!Getting the power valve fitted and the servo working was like one of the biggest mine-fields since the Somme
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Yeah, the cables are clearly numbered 1 & 2. In my case they didn’t match up. I had to cut some outer off of one as well, to make it fit and work.
unbelievable!Getting the power valve fitted and the servo working was like one of the biggest mine-fields since the Somme
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I sounds like a dog!
Seriously though, it sounds a bit ‘clicky’ to my ear. A bit hesitant as well maybe...
It’s really hard to tell without being there and hearing the whole range of sound frequencies...P.S. Have you done your power valve yet?...
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Does my DT sound properly?
https://youtu.be/Id1jsvah8T8 -
Any old 2litre bottle top will plug the hole...
I didn’t want to say before but does that piston look like it was partially heat seized? Those are vertical score marks, no?
Not that I haven’t run a lot worse before 🤪
Sort out the power valve and see how it runs after bud. Then worry about if the top ends rattling. It could even be too much back pressure from an over closed power valve making the piston slap??P.S. is that the side bottle, or the one that sits on top of the inlet manifold?...
My eyes aren’t as good as they once were... -
Any old 2litre bottle top will plug the hole...
I didn’t want to say before but does that piston look like it was partially heat seized? Those are vertical score marks, no?
Not that I haven’t run a lot worse before 🤪
Sort out the power valve and see how it runs after bud. Then worry about if the top ends rattling. It could even be too much back pressure from an over closed power valve making the piston slap??P.S. is that the side bottle, or the one that sits on top of the inlet manifold?...
My eyes aren’t as good as they once were... -
@SpookDog It changed sound when I tried to adjust power valve... Maybe I should try to put it in position it was before.
Where is yeis bottle supposed to be? -
@Lukas55 IF YOUR cylinder has been rebored but your pv hasn't been machined the piston will hit your pv check the piston with the exhaust off again
