KTM Power Valve

[jrbmx1]

I have done so many top ends but,I just rebuilt the top end for the first time on a KTM 125 SX. I did not move the power valve linkage or arm. I slid the cylinder down on the new piston, it slid right down easy. My question is it possible to miss the linkage and not have the power valve connected? The reason I ask is that I added a pipe, head, Delta V-2 and my son said it rips but has no bottom end. Is there a way to check this power valve?
Thanks

 

[Jaybird]

Did he feel there was good bottom end before the rebuild? My 125sx has very little bottom with the stock base gasket.

 

[zilla]

Pul the pipe off, then the right side power valve cover.. Youn can see if it is hooked up.. Did you re-insta the little wire gizmo that locks it in place??

zilla

 

[jrbmx1]

Jaybird,
He said it had some bottom end before the rebuild (have 1 more tooth on the rear sprocket), now there is none. Runs great mid to top. Does not miss or sputter, just zero bottom.

 

[jrbmx1]

Zilla,
When I took the cylinder off it just slid off, I did not dis-connect anything for the linkage so I do not know of anything holding it in place. After installing the new piston, I just slid the cylinder back on thinking the actuator arm just slips in place? Now I am concerned that there is something missing.

 

[zilla]

Well if you didn't re-connect the linkage then, it is not hooked up.. you need to pull the pipe off, and remove the PV cover.. You will see a ball connection.. The rod comes out of the cases and has the female ball connector on it.. It just snaps on to the ball on the PV arm.. Then you need a smal wire keeper.. Therrre is a smal hole in the ball part where the keeper goes after assembly to hold everything in place.. You probably don't have it.. You need to order one and install it.. I would reconnecting the PV and run it with out the keeper till you get one.. If you need some pics let me know and I'll take mine apart and take a picture..

zilla

 

[Milo]

I just got done doing a top end rebuild on my 250exc,after the rebuild i ended up with the exact same problem,no bottom all mid to top. I installed the two barrel valve on the wrong side(left to right-right to left). The bike ripppp's now. You can pull the pipe off and watch the power valve move by manually moving the disconected actuator rod. When i did this the power valves was not moving like the should ,try this and watch the power valve movement.

Milo

 

[jrbmx1]

I think I have it now, I will fire it up tomorrow to see. The linkage was not locked in. The 02 125 SX does not have a clip for the linkage. You just have to align the linkage and slide the cylinder down on the actuator while aligning it and it locks in place. The KTM dealer showed me the manual for the older 125's and they had a wire clip to lock the linkage together. Thanks for all of the feedback.
Zilla is one heck of a guy to make an offer of tearing down and sending me pictures, the world could use more people like him.

 

[jrbmx1]

It is now working! Thanks for the tips and feedback. Just have to line up the arms as you slide the cylinder down. Its kinda like a ball and socket.