Power valve sticking on 16/17 KTM 125's

brocsdad
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brocsdad
Edited Date/Time 6/7/2018 1:18pm
I have heard about the power valves sticking on the 16/17 KTM 125's. Well I was prepping my sons bike Saturday and took it for a spin up the street and I noticed it wouldn't rev out. So I pulled the cover to watch and see If the PV was working and nothing. It finally broke loose and revved out but it was extremely slow to return and the power was erratic. I'm going to take it apart in the next day or so and clean everything but the bike only has 10 hours.

Has anyone else had the issue? If so how did you fix it?

Thanks!
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CarlinoJoeVideo
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CarlinoJoeVideo 1/30/2017 12:08am
1/30/2017 12:08am
My 16 125 has about 40 hours on it and my power valve does a simaler thing. It's feels free but there is a sticky point. I've narrowed it down to the power valve arms. The way the are machined there's a point that the pin can't smoothly slide.
The bottom photo shows the OEM arm(black) vs new arm(gold)made by F1moto.

You can see on the OEM arm there's a flat spot where the sliding pins get stuck on my bike.

I order the new set : http://m.ebay.com.au/itm/192076490596?_mwBanner=1
Hopefully can install mine this week and test them out!
brocsdad
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brocsdad 1/30/2017 6:49am
1/30/2017 6:49am
Thanks for the info!

I wonder if you could just round out the OEM with a dremel?

Another question?
When assembling the Power Valve is it a must to measure the distance of the flap with the tool as shown in the manual? Could I just measure the distance before and after with calipers or does it actually move when taking everything apart?

They also recommend adjusting the deck height with the dial indicator. I was hoping to could measure the current gaskets or do a squish test.

Thanks!
CarlinoJoeVideo
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CarlinoJoeVideo 1/30/2017 10:00am
1/30/2017 10:00am
brocsdad wrote:
Thanks for the info! I wonder if you could just round out the OEM with a dremel? Another question? When assembling the Power Valve is it...
Thanks for the info!

I wonder if you could just round out the OEM with a dremel?

Another question?
When assembling the Power Valve is it a must to measure the distance of the flap with the tool as shown in the manual? Could I just measure the distance before and after with calipers or does it actually move when taking everything apart?

They also recommend adjusting the deck height with the dial indicator. I was hoping to could measure the current gaskets or do a squish test.

Thanks!
When taking it apart I didn't notice anything that needs to be measured. I didn't aadjust the actual adjuster, just took the arms and flap out. Everything should just pop back into place.

I'm going to test the new arms and I'll try to round out the OEM ones to see if it helps.

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arm2004
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arm2004 1/30/2017 11:44pm
1/30/2017 11:44pm
I received a set of the power valve arms but could not get them installed. The arm pin was in the wrong spot, if you look at the above pics look at the pin placement on the black arm and the gold arm (gold pin is closer to the rectangle cut out). The left arm has a arm stop that the bolt goes though, with the pin off the bolt hole is off. this is for a '17 125sx not sure about the '16 assume they are the same. I contacted F1 they seemed willing to help but have not seen anything yet. I seen a post on KTM talk about a guy having problems with them and was told that rounding the stock arm would make the problem worse- i dont know and have not tried rounding the stock ones.
brocsdad
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brocsdad 1/31/2017 7:32am
1/31/2017 7:32am
arm2004 wrote:
I received a set of the power valve arms but could not get them installed. The arm pin was in the wrong spot, if you look...
I received a set of the power valve arms but could not get them installed. The arm pin was in the wrong spot, if you look at the above pics look at the pin placement on the black arm and the gold arm (gold pin is closer to the rectangle cut out). The left arm has a arm stop that the bolt goes though, with the pin off the bolt hole is off. this is for a '17 125sx not sure about the '16 assume they are the same. I contacted F1 they seemed willing to help but have not seen anything yet. I seen a post on KTM talk about a guy having problems with them and was told that rounding the stock arm would make the problem worse- i dont know and have not tried rounding the stock ones.
Well great...

I just placed an order last night.

As far as the grinding my friend smoothed out his with a dremel and he said it worked fine. I was going to order the F1 arms to ensure they were right and not chance me grinding a little too much off.

I sent a message to Steve to verify the issue was resolved. After reviewing the pics you can see a difference in the pin location from the OEM.
F1 Moto
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F1 Moto 1/31/2017 8:03am
1/31/2017 8:03am
There was a manufacturing error in the first batch of f1 moto arms..
Second batch due to complete today.
These will be sent out free of charge today to the people who have purchased already.
brocsdad
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brocsdad 1/31/2017 8:08am
1/31/2017 8:08am
F1 Moto wrote:
There was a manufacturing error in the first batch of f1 moto arms.. Second batch due to complete today. These will be sent out free of...
There was a manufacturing error in the first batch of f1 moto arms..
Second batch due to complete today.
These will be sent out free of charge today to the people who have purchased already.
Good News!

Thanks Steve!
CarlinoJoeVideo
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CarlinoJoeVideo 1/31/2017 9:04am
1/31/2017 9:04am
F1 Moto wrote:
There was a manufacturing error in the first batch of f1 moto arms.. Second batch due to complete today. These will be sent out free of...
There was a manufacturing error in the first batch of f1 moto arms..
Second batch due to complete today.
These will be sent out free of charge today to the people who have purchased already.
Ok thanks, I just got mine and was going to install them today. I'll update you guys in a few hours.
brocsdad
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brocsdad 1/31/2017 9:57am
1/31/2017 9:57am
F1 Moto wrote:
There was a manufacturing error in the first batch of f1 moto arms.. Second batch due to complete today. These will be sent out free of...
There was a manufacturing error in the first batch of f1 moto arms..
Second batch due to complete today.
These will be sent out free of charge today to the people who have purchased already.
CarlinoJoeVideo wrote:
Ok thanks, I just got mine and was going to install them today. I'll update you guys in a few hours.
If you just received them they are the 1st batch according the above response.
arm2004
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arm2004 1/31/2017 12:17pm
1/31/2017 12:17pm
CarlinoJoeVideo- start with the left side of the bike that is where i run into the problem. I never tried the right side but from my measurement they were off a little also- this is for the (1st batch of arms i think) as far as grinding talk to Jbone Motosport (great guy and recommend his work to any KTM owner) i think he has a fix, i never got into with him as i had the arms on order when we discussed this problem.
CarlinoJoeVideo
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CarlinoJoeVideo 1/31/2017 1:35pm
1/31/2017 1:35pm
Hey guys, I got both of the F1 moto arms installed. Riders right went it with no problems.

The riders left I had to shave a hair off the spot where the pin fits into the triangle piece. As seen in this photo.


Movement by hand is much smoother and I don't feel any binding like I did before.
brocsdad
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brocsdad 1/31/2017 1:59pm
1/31/2017 1:59pm
CarlinoJoeVideo wrote:
Hey guys, I got both of the F1 moto arms installed. Riders right went it with no problems. [img]https://p.vitalmx.com/photos/forums/2017/01/31/172884/s1200_IMG_9065.jpg[/img] The riders left I had to shave...
Hey guys, I got both of the F1 moto arms installed. Riders right went it with no problems.

The riders left I had to shave a hair off the spot where the pin fits into the triangle piece. As seen in this photo.


Movement by hand is much smoother and I don't feel any binding like I did before.
Ok,

From the response I thought the new ones were not ready?

arm2004
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arm2004 1/31/2017 2:17pm
1/31/2017 2:17pm
That looks about right mine was off by 1.4mm on the left side- not much but just enough to put the bolt hole off if you do not modify the stop arm pin hole. Glad to see the right side works my pins was off by 1,2mm on the right side but dont see a reason they would not work. Be interested in a ride report- if you notice any difference.
CarlinoJoeVideo
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CarlinoJoeVideo 1/31/2017 4:19pm
1/31/2017 4:19pm
CarlinoJoeVideo wrote:
Hey guys, I got both of the F1 moto arms installed. Riders right went it with no problems. [img]https://p.vitalmx.com/photos/forums/2017/01/31/172884/s1200_IMG_9065.jpg[/img] The riders left I had to shave...
Hey guys, I got both of the F1 moto arms installed. Riders right went it with no problems.

The riders left I had to shave a hair off the spot where the pin fits into the triangle piece. As seen in this photo.


Movement by hand is much smoother and I don't feel any binding like I did before.
brocsdad wrote:
Ok,

From the response I thought the new ones were not ready?

These are supposedly the batch with the wrong pin hole. Like I wrote above, I had to slightly modify the hole to fit.(see photo above with the screw driver pointing at the pin.

F1 Moto
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F1 Moto 1/31/2017 8:51pm
1/31/2017 8:51pm
Latest arms posted today.
Usually takes about a week shipping to the US.
Please keep the feedback coming on the revised design.
Thanks in advance.
brocsdad
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brocsdad 2/1/2017 10:33am
2/1/2017 10:33am
Since the KTM 150 has the same design the arms would also work for the 150?
CarlinoJoeVideo
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CarlinoJoeVideo 2/1/2017 5:24pm
2/1/2017 5:24pm
brocsdad wrote:
Since the KTM 150 has the same design the arms would also work for the 150?
Yes they will fit the 150. But today was my first day riding with them and my first impression is that it might be worse. I'm going to ride again on Friday and do back to back test with OEM and F1 arms. Don't want to give an official opinion yet because I want to double check at a different track with different elevation.

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F1 Moto
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F1 Moto 2/1/2017 5:34pm
2/1/2017 5:34pm
Hi Joe,
Probably best to wait for the replacement arms to arrive and base your testing on these.
We know the originals were wrong & have corrected this.
Replacements on the way to all customers.

Regards
Steve
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CarlinoJoeVideo 2/1/2017 5:44pm
2/1/2017 5:44pm
F1 Moto wrote:
Hi Joe, Probably best to wait for the replacement arms to arrive and base your testing on these. We know the originals were wrong & have...
Hi Joe,
Probably best to wait for the replacement arms to arrive and base your testing on these.
We know the originals were wrong & have corrected this.
Replacements on the way to all customers.

Regards
Steve
Thanks Steve, I'll try the new ones as well. I'm not sure if the pin placement will have any effect, do you?

Was there anything else changed on version 2?
F1 Moto
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F1 Moto 2/1/2017 6:07pm
2/1/2017 6:07pm
Yes,track profile change as well.
Hopefully smooth operation with good performance.Please keep feedback coming preferably by PM.
CarlinoJoeVideo
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CarlinoJoeVideo 2/3/2017 3:05pm
2/3/2017 3:05pm
Hey guys, so little update. I also sent more detailed info to Steve at F1Moto. I didn't have any luck with the version 1 of their PV arms.

They felt smooth to the hand, but once in riding conditions they were sticking more than stock. Not sure how bad your stock ones are. I've also replaced the rubber orings on all the moving parts that has to do with the power valve.
latech
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latech 4/25/2017 5:04pm
4/25/2017 5:04pm
CarlinoJoeVideo wrote:
Hey guys, I got both of the F1 moto arms installed. Riders right went it with no problems. [img]https://p.vitalmx.com/photos/forums/2017/01/31/172884/s1200_IMG_9065.jpg[/img] The riders left I had to shave...
Hey guys, I got both of the F1 moto arms installed. Riders right went it with no problems.

The riders left I had to shave a hair off the spot where the pin fits into the triangle piece. As seen in this photo.


Movement by hand is much smoother and I don't feel any binding like I did before.
brocsdad wrote:
Ok,

From the response I thought the new ones were not ready?

CarlinoJoeVideo wrote:
These are supposedly the batch with the wrong pin hole. Like I wrote above, I had to slightly modify the hole to fit.(see photo above with...
These are supposedly the batch with the wrong pin hole. Like I wrote above, I had to slightly modify the hole to fit.(see photo above with the screw driver pointing at the pin.

Okay so I have a question since this is my first two stroke and the first power valve I'v messed around with but when I took the left and right side cover off and popped the armature off the end of the knob and the only thing that seems to move easily is the piece the armature was attached too. I figured the that you could move the piece with the groove cut out (Gold looking piece)with the pin in it which to me looks like it would be the piece that opens the valve and mine is super hard to move which is why I'm not sure if its made to move easily or not. Thanks!
CarlinoJoeVideo
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CarlinoJoeVideo 4/25/2017 5:48pm
4/25/2017 5:48pm
Hey so I asked a guy at KTM and he said they are supposed to have some resistance. If you feel like yours are sticking very bad, you can do a whole tear down and see which part is sticking? I did it when I replaced my top end and had the .cylinder off.
latech
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latech 4/27/2017 8:48pm
4/27/2017 8:48pm
CarlinoJoeVideo wrote:
Hey so I asked a guy at KTM and he said they are supposed to have some resistance. If you feel like yours are sticking very...
Hey so I asked a guy at KTM and he said they are supposed to have some resistance. If you feel like yours are sticking very bad, you can do a whole tear down and see which part is sticking? I did it when I replaced my top end and had the .cylinder off.
Also what the parts catalog calls the control drum (part #11 from the exhaust control diagram) with the o ring on it and it inside the hole could you turn yours easily by hand? Here is a link to diagram https://www.rockymountainatvmc.com/oem-schematic/5 then click on exhaust control and it should bring up diagram.


SXRIDER17 5/23/2017 6:36pm
5/23/2017 6:36pm
Ya i have same problem right now , part number 11 (outer power valve )wont spin at all by hand ) not sure why its stuck.
latech
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latech 5/23/2017 6:55pm
5/23/2017 6:55pm Edited Date/Time 5/23/2017 6:57pm
SXRIDER17 wrote:
Ya i have same problem right now , part number 11 (outer power valve )wont spin at all by hand ) not sure why its stuck.
They will rust and need replaced (part 11) or you might get away with fine sand paper to remove rust film on them if there is any. I replaced mine which helps alot but it still has issues which I'm working on.New silencer 1st,then jd jet if that doesnt work then aftermarket pv control arm next then reed valve if needed.Mine was rusted because the gasket on pv cover was not sealing good.
SXRIDER17 5/23/2017 6:57pm
5/23/2017 6:57pm
Have fmf 2.1 , lectron mule hv so no jetting lol and vforce 4 rs on it.
SXRIDER17 5/23/2017 7:00pm
5/23/2017 7:00pm
Just did top end this weekend and noticed the power valve but want to go riding tm so i just put it back together , taking power valve apart this weekend and ill check bearing, thanks.

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