So far I have: adjusted the valves to 0.10mm intake/0.15mm exhaust, cleaned and adjusted the gap on the plugs, and checked over the TB boots to make sure there isn't an air leak there.
The left intake valve was way, way off, so we figured that might have been the cause of the problem.
Afterward, the idle was a bit better but still sort of low. On the verge of stalling. So we then adjusted the idle, with the screw on the left throttle body, to about 1000 rpm.
Now it idles fine...
...but taking it out on the road, the bike is now incredibly sluggish. It'll get up to speed but seriously lacks power compared to before.
I have yet to balance the throttle bodies, so I'm wondering if that's what's missing, or if I messed up on one of the other steps. We triple checked the measurements though.