Headlights & Stator & Rectifier

[Crash4723]

I bought a 2008 Shenke 150cc scooter and what I noticed right off the bat is that the headlights were super dim at idle and not very bright when revved up. I rode it home (about 25 miles) and I also noticed that when I grabbed the brake the headlights became bright. I thought it was a problem with the ground so I traced & cleaned with a wire brush the negative lead from the battery, the wire to the frame, and the wire to the engine.

This did not resolve the issue. I know the headlights work off the A/C circuit and the tail and turn lights work off the D/C circuit. Now at an idle the headlights are off. When I take off from a stop sign the headlights come on but are very dim. When I hit the brake lights (While cruising at about 6k RPM's) the headlights become bright and stay that way until I come up to a stop sign again and then they dim and go off again. It seems that the only way I can get the headlights to come bright again is to hit the brakes when I am above 4k RPM's or so.

So where is the most likely spot to start diagnosing? I already ordered a new rectifier cuz they are cheap. Is it possible/likely that I have an issue with my stator? How do I even test my stator?

-Crash