- There is no connection between the battery treatment area, and the areas related to the treatment of the front forks. The front sprocket area is also a separate area and independent of the other two areas. That's why I don't see a connection between the repairs that was recently carried out in the garage and the problem you claim appeared after that repairs. The front sprocket problem It seems to me not related to the last mechanic's work.
- As it can be seen in the video, your chain is very rusty, the front sprocket is already quite worn, I understand that both require replacement, and then it is customary to replace everything as a set, meaning also the rear sprocket.
- I'm not sure I understand what the round black plastic part is. The electric wire that reaches the neutral gear sensor passes in front or the front sprocket, this wire should sit inside his rail/slot. Maybe the front sprocket cover was tightened over the wire when the wire was not in his slot, so it damaged the wire?
Yes
In the video it was hard to see because the camera was constantly moving, but you can download a stills image here, zoom in on the front sprocket and I'll try to see again. From the video I got the impression that the sprocket and the chain both look damaged to me.