Powervalve setting

[Jonnymotard]

Hi everyone,

I'm a bit new to this so please bear with me!. I recently bought a 2007 DTX and I'm really pleased with it. Ater buzzing around for a couple of weeks I started to fiddle around a bit to improve performance. It has a full Dep exhaust system fitted and the restrictor wire mod to the speedo has been done. I was convinced that it was still heavily restricted however so I took off the exhaust (needed derusting anyway) and had a look up to check the position of the power valve ( as recommended on one of these forums ~ thanks). Looked like the valve was retarded so after noticing the locking pin section had broken off anyway (previous owner?) I undid the centre bolt and rotated 180' so it looked flush inside the exhaust port. I then retightened the centre bolt, put the exhaust back on and tried it. The difference was immediate with the noise and my top end went from 60 to 75. The only thing is the acceleration isn't smooth. If you welly it and get in to the power band in the low gears this transfers through the gears and it goes like a rocket but if you are poodling along at 40 and want a sudden burst it goes flat and takes time to pick up. My question is should I stick with and get the top end benefit (when it kicks in!) or should I try to adjust the power valve back slightly to improve pick up in higher gears? Be interested to know if anyone has had similar problems.

Cheers

Jon

[2 Wheels]

Hello Jonny,

Well that is your choice. If you find that a lot of your riding is between 35 an 50mph then its probably best to try and retard the PV back a bit to give you more bottom end performance.

Welcome to the YOC

[Jonnymotard]

Hello Jonny,

Well that is your choice. If you find that a lot of your riding is between 35 an 50mph then its probably best to try and retard the PV back a bit to give you more bottom end performance.

Welcome to the YOC

Thanks a lot 2wheels,

Nice to get a reply so quick! I have been playing with the adjustment a bit since my post but so far it seems all or nothing! I reset to original then went about 90' to the left. It's definitely smoother but I'm missing that squirt of speed and top end was back to 60 (not much good for dual carriage ways!).

Anyway thanks for the reply ...... I'll keep tinkering.

Nice 1

Jonny

[2 Wheels]

Thanks a lot 2wheels,

Nice to get a reply so quick! I have been playing with the adjustment a bit since my post but so far it seems all or nothing! I reset to original then went about 90' to the left. It's definitely smoother but I'm missing that squirt of speed and top end was back to 60 (not much good for dual carriage ways!).

Anyway thanks for the reply ...... I'll keep tinkering.

Nice 1

Jonny

Does it not have a working servo for the PV,, with cables

EDIT: like this http://www.yamahaclub.com/forums/topic/20583-de-restricting-my-dt125r/page__hl__derestricting__st__30

[Jonnymotard]

Hi Again,

The servo I believe is working. When you ign on the valve readjusts to a set position when the centre bolt is loose. Once the bolt is tight you can ign on and off and nothing moves same if you throttle .... is this right?. Seems to run OK like this but means the PV isn't doing anything I guess. Could this explain why it gets boggy when the valve is set full open?. Is the centre bolt supposed to be left loose?. I'm missing something somewhere!

Cheers

Jon

[Airhead]

Too right it's not right, the pulley should be unable to move without taking the PV with it, I suggest you have a look at the back of the pulley and the PV end to see how this can be happening, Also while you're at it...try moving the pV (with a spanner) it should move easily

[Jonnymotard]

Too right it's not right, the pulley should be unable to move without taking the PV with it, I suggest you have a look at the back of the pulley and the PV end to see how this can be happening, Also while you're at it...try moving the pV (with a spanner) it should move easily

Thanks I'll have a closer look at the pulley. At the moment I have it rotated forward and with the centre bolt tightened it doesn't move when you ign on or throttle. Strangely the bike doesn't seem to run too bad but the acceleration kicks in a bit suddenly. Also the centre bolt has a spring washer which loks like it's there to hold the valve tight (but maybe not original?). The notched part in the pulley has broken off so you have to guess the original position a bit. I can't help wondering if the spring washer has been added to hold it in place (either forward or backward. Let you know how I get on.

Cheers

[Jonnymotard]

Thanks I'll have a closer look at the pulley. At the moment I have it rotated forward and with the centre bolt tightened it doesn't move when you ign on or throttle. Strangely the bike doesn't seem to run too bad but the acceleration kicks in a bit suddenly. Also the centre bolt has a spring washer which loks like it's there to hold the valve tight (but maybe not original?). The notched part in the pulley has broken off so you have to guess the original position a bit. I can't help wondering if the spring washer has been added to hold it in place (either forward or backward. Let you know how I get on.

Cheers

Hi again,

Looks like something wrong with the servo cycle!. Because the notched part of the pulley had broken off someone has put a large thin flat washer behind the pulley wheel so) that when you tighten it it stays in that position (anywhere between fully back and fully forward). when you take this out and try to do the cleaning cycle it just rotates clockwise and stays there!. There is no movement when you rev the engine at all so in this case it rides with it retarded (no top end). at the moment I have 'fixed' it in place in the forward position to give me some top end.any idea why the servo behaves like this?