2017 ktm 50 sx sputtering top end

jsippola
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jsippola
2017 ktm 50 sx sputtering on the top end. Carb has been cleaned more than once, reeds inspected, new CDI/stator. That didn’t help so then I replaced the top end on it and still am having the issue. Next I’m thinking of replacing the crank seals. Any ideas on the cause? Also, I’m linking a video of the bike. Thank you

https://youtu.be/w3lxi4DY1IA
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Factor E
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Factor E 3/26/2020 8:08am
3/26/2020 8:08am
First , you have gone through most of the common parts.
Post a picture of how the connectors are bolted to the case for ground. Could be the issue.
A worn needle in carb have been known issues.
Spark plug boot.


jsippola
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jsippola 3/26/2020 12:45pm
3/26/2020 12:45pm
Was running fine till the other day.
jsippola
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jsippola 3/26/2020 12:45pm
3/26/2020 12:45pm
Factor E wrote:
First , you have gone through most of the common parts. Post a picture of how the connectors are bolted to the case for ground. Could...
First , you have gone through most of the common parts.
Post a picture of how the connectors are bolted to the case for ground. Could be the issue.
A worn needle in carb have been known issues.
Spark plug boot.


Needle was replaced last weekend.

The Shop

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Factor E
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Factor E 3/27/2020 9:57am
3/27/2020 9:57am
Look at the ground wires to the motor. You should have two connectors bolted in the same spot. one from coil an other from stator. I found working on three of these at the same time the coil wire(small eyelet)must be against the case first. It took many hrs taking things apart and swapping parts to make them run like they should. Each you had different running issue. Two had the ground issue.
Check this and test ride.
Factor E
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Factor E 3/27/2020 10:14am
3/27/2020 10:14am
Just listened to vid. Did you take power valve apart for top end? or just pull complete cyl and head together.
Sounds like powervalve stuck or not connected to diaphragm.
Pull pipe put finger in to manually move valve.
1
dkurtd
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dkurtd 3/28/2020 5:54pm
3/28/2020 5:54pm Edited Date/Time 3/28/2020 5:54pm
Factor E wrote:
Just listened to vid. Did you take power valve apart for top end? or just pull complete cyl and head together. Sounds like powervalve stuck or...
Just listened to vid. Did you take power valve apart for top end? or just pull complete cyl and head together.
Sounds like powervalve stuck or not connected to diaphragm.
Pull pipe put finger in to manually move valve.
KTM 50 sx's don't have a powervalve.
mtnbk3
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mtnbk3 6/18/2021 5:18am
6/18/2021 5:18am
Did you find a solution to this issue? My boys 2017 KTM 50sx sounds exactly the same. Ive tried about everything you have with no success.

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