Yamaha DT 125 DERESTRICTING

[Lukas55]

@SpookDog So It is rebored but I don't now on how much because previous owner did it... But I don't belive it is too much... So the sound it makes on higher rpms is not that big deal?

[SpookDog]

I was looking at the utube clip, not a pic. You can see the vertical seam where the 2 halves of the power valve fit together. It’s almost 2/3 to 3/4 closed!

Yes, move the power valve that way! (anti-clockwise) The pulley should fit snug back onto the diamond of the power valve after without adjusting the cables too much. You should be able to run your finger from the piston to the exhaust port outer edge without feeling any lips or hard edges. It should be smooth...

[Lukas55]

@SpookDog I opened it all the way up! I hope it won't scratch my piston... Thanks for help.

[SpookDog]

If it’s open it won’t touch the piston! Open means the valve isn’t blocking your view of the piston.
Show me a pic of what you mean by ‘open’ please...

I fear we might be losing something in translation..

[Lukas55]

@SpookDog This is how it looks. https://i.postimg.cc/Dmm09szC/IMG-20201003-140839.jpg
Can not really see how much it is on picture...

[Calum]

Yeah, the valve is clearly not flush with the exhaust port.

It should be flush with the exhaust port when done.

[SpookDog]

Please turn it anti-clockwise till you can see the most of the piston without it being occluded by the power valve. I don’t know how else to say it...

[SpookDog]

You should not see any of the power valve

[Calum]

@Lukas55 Took ages to find this post, thank God for the Search function.

https://www.youtube.com/watch?v=9eopT_gyAo4

I had the engine out my DT today, so under an inspection lamp I've taken the courtesy of creating a very short sweet video of the powervalve in its fully open, to fully closed back to fully open state.

Yours should match that operation.

[SpookDog]

@Lukas55

Be nice to know how you got on, bud?

[Lukas55]

I'm sorry for my inactivity... Thanks, everyone for helping me out! I opened the power valve and removed the rubber tube that is on top of the airbox. Now the bike gets much more air and breathes as it should, it goes like a beast. THANKS, EVERYONE!!