2017 yz250f randomly acting up and shutting off

2017yz250f
Hello I recently picked up a low hour 2017 yz250f for my son it ran perfect for 3 months and then all of a sudden started randomly shutting down periodically. It will run fine for hrs then just act up and randomly die, to date I have


-replaced fuel pump
-unplugged the kill switch and ran bike no change
-applied di-electric grease to all connections
-tested all sensors with ohm meter
-tested coil hot and cold with a ohm meter
-tested stator/inspected
-checked over the harness all good
-cleaned the throttle body
-checked valve clearance
-checked compression
-drained and added fresh fuel
-air filter is ok
-removed and tested the neutral safety switch

this bike is driving me insane
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Marsbar299
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8/28/2022
Location
Rochester, WA US
Marsbar299 9/24/2022 7:37pm
9/24/2022 7:37pm
Sound like a ground in the wiring causing the bike to randomly shut off, but you mentioned going over the wiring harness, so I'm not quite sure.
stone881
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12/26/2014
Location
Fruita, CO US
stone881 9/24/2022 8:01pm
9/24/2022 8:01pm
What about the spark plug cap? On my KTM it was arcing and causing all sort of weird problems. I don't know about a Yammy, but mine was like 20 bucks and just screws onto the wire.
1
2017yz250f 9/25/2022 3:29am
9/25/2022 3:29am
The cap on this particular bike is over$100 canadian. I did test the cap several times with a meter both hot and cold it tested perfect.
2017yz250f 9/25/2022 3:32am
9/25/2022 3:32am
Marsbar299 wrote:
Sound like a ground in the wiring causing the bike to randomly shut off, but you mentioned going over the wiring harness, so I'm not quite...
Sound like a ground in the wiring causing the bike to randomly shut off, but you mentioned going over the wiring harness, so I'm not quite sure.
It could be, Its a strange issue one would think a broken or shorted wire would an issue that would arise and remain. This issue started out of no where and is now an occurrence on every ride sometimes its just a bog and a pop and the bike will otherwise run ok, other times you can only get the bike to move a few feet at a time and it will shutoff.

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Factor E
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9/22/2011
Location
So Cal, CA US
Factor E 9/25/2022 5:35pm
9/25/2022 5:35pm Edited Date/Time 9/25/2022 5:38pm
Change the plug
Try another ECU
Test battery
Try another tank

The bike runs-Not mechanical
Random issues-Electrical
2017yz250f 9/25/2022 6:34pm
9/25/2022 6:34pm
Factor E wrote:
Change the plug
Try another ECU
Test battery
Try another tank

The bike runs-Not mechanical
Random issues-Electrical
Plug has been changed 3 times, tried 3 different fuel pumps. Bike has no battery kick start only. I do not know anyone with an ecu to try
Factor E
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952
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So Cal, CA US
Factor E 9/25/2022 11:15pm
9/25/2022 11:15pm
Rectifier or Condencer?
2017yz250f 9/26/2022 1:46am
9/26/2022 1:46am
Factor E wrote:
Rectifier or Condencer?
What is the purpose of the condenser thats under the seat?my maual does not show how to test it
Factor E
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Posts
952
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Location
So Cal, CA US
Factor E 9/26/2022 6:54am
9/26/2022 6:54am
Stores energy
2017yz250f 9/26/2022 8:57am
9/26/2022 8:57am
Factor E wrote:
Stores energy
That would be a capacitor?

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