Rear derailleur jumping

[mangekyo]

Im having a problem with my derailleur jumping after I installed the Bafang motor and chainwheel:

https://streamable.com/04o2bp

Why is this happening and how can I fix it?

 

[Tommm]

Im having a problem with my derailleur jumping after I installed the Bafang motor and chainwheel:

https://streamable.com/04o2bp

Why is this happening and how can I fix it?

Your chain is busted up in that spot and that part is the most sensitive in your drivetrain to show symptoms. Use master links to join the chain next time instead of re-using pins. You can get master links $0.5 each on aliexpress for any speed.

 

[mangekyo]

I am using kmc missing link