Yamaha DT 125 DERESTRICTING
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Here is video of power valve, maybe its something wrong with it... If video quality is bad I will make better one tomorrow...
https://youtu.be/naA3Zt0piGs -
@Lukas55 the powervalve seems to operate as expected. It'd be worth taking the exhaust off to see if the valve is in the open position when it's supposed to be. It can be fitted 180° out. And to check there's no restrict ions in the exhuast it self.
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I have it for about 3 months and it was like that when I bought it. It had 13-57 gearing so I thought it's because of that but when I bought 16t front sprocket then I noticed it's something wrong... The piston and bearings in the crankshaft are changed 400km ago...
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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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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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@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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Does my DT sound properly?
https://youtu.be/Id1jsvah8T8
