Won't open power band 99 125 sx

logworksbyjon · 01-28-2012, 01:50 PM

I have a 99 125 sx and a 2001 yz 125, the yz runs like a wild ape just like it should but the ktm runs good except when the power band should kick in and really has only half the power of the yz. I have redone the top end and removed the power valve and cleaned everything very well but I am still not getting that jolt of power at high rpm like it should. Any suggestions where to start, the ktm has a fmf fatty gold pipe and silencer on it and factory reeds as far as I can tell. I have never adjusted the power valve can any oun point me in the direction of instructions of how to adjust the power valve on my 99 ktm 125, thanks.

bajadog · 01-30-2012, 07:28 AM

http://www.youtube.com/watch?v=XTciYyryJuM

brasshole · 02-02-2012, 07:49 PM

ok bro, belive me i just went thru this prob on a 144 i just bought.
sounds like you didn't hook the power valve back up, but here are other things to try.

1. open the the lil cover on the left side (not exhaust pipe side) it has the lil hose coming out of it, start the bike and look in there give it a lil gas and see if it moves up and down you'll see a little mark on the metal. if you have no movement then you need to pull the top end and make sure the fork of the power valve meets the accuator arm and sits inside the fork. also you can pull the pipe and behind it there is another power valve window there just like on the left side you can pull that one off and look in there to see if your arms are lining up

2. if you have movement in the window on the left side, you may not have timed the power valve correctly. when the valve is open all gates/ power valves should be all the way open and vise verse when closed they should be in the closed position. mine was not correct and all the way open only 2 where open all the way. my fork was also not hooked up to my accuation arm.

3. now if all is right and it still doesn't feel like it is working the nut on the right side its pretty big is where and how you adjust the hit of the power valve, and there a bunch of right ups on how to do so but I'm tired of typing lol

gmoss · 02-05-2012, 07:40 PM

Check the timer. I have seen the balls in the timer of 2 bikes recently come out and get lodged in the wrong spot, keeping the PV open. If the balls aren't in the right spot, the PV won't work correctly.