Alright, I have the same problem. I took the cover off (little oil) and one of the magnet was pretty (black see pic). I thought I had it! checked the output on AC: 20 to a 100V varying revs. The voltage barely flicker up when I put the meter on a good battery while engine is compare to non running.When running I loose a 0.1-0.3V when I put high beam, signal, brake.
Is it safe to assume it is the rectifier? Bike is a garage 05 with 6000 miles.
05 Black S3 M4 stubby, fat black bars, CRG's, GSXR1000 calipers
06 R6 50th anniversary
96 Ducati 900SS All tricked out
96 Ninja 500 racer