Just had the seat off my bike for the 1st time.
There's a small box under there with a *** on it. I'm assuming it's an O2 controller as featured on here. It's currently set with the line on the knob to the mark on the box. Fully off? Don't know if there's a fuel controller or not, or filters. It's on standard exhaust.

What happens if I turn the knob?

There was no mention of it when I bought the bike and no paperwork on it.

Bike pops a lot on the over run with a closed throttle- is this related.

Thanks for any advice in advance

Mark