Seems like it was the gas. Until I get the new battery in, I won't be able to verify it.
In the 10 mins it spent idling, no-load revving the motor went from popping/struggling to get above 5k to zinging up and down like it used to. Hopefully under load it she will be her old self again.
good, i hope it's cheap and easy. nothing more frustrating than staring at a beautiful bike that's not acting right.