I trust you more lmao. I’m pretty sure he’s got no clue what he is doing at this point. I found a guy in my area who does atv and side by side electrical work. It also turns out he is a friend of my uncle so he should have it fixed no problem.
Agree, Yamaha electrics aren't the best to start with, especially older models and it sounds like someone who thinks they know what they are doing has been messing about. Thinking you may have 2 separate problems with the max speed and cutting out though.Its not CDI or stator dammit - they have nothing to do with loss of lights. If your friend truly had any electrical knowledge he would understand this.
99.9% likely the problem is in the changed 're-wiring' that he did and most likely related to the switch that has replaced the key switch.
You can trust him or us, but not both.