The bike should keep the battery at about 13.5 volts when the engine is running at anything over 2000rpm. No matter what you switch on, as it's the job of the regulator to keep this voltage constant.
If you have a fault however, which is shorting the live to chassis, then the alternator cannot provide enough charge and the system will drain. That's why there are fuses in the system to blow if this happens.
Either you have a faulty regulator - even new ones can be duff, or theres a fault in the wiring.
I'd check the output of the alternator at various revs, then the output of the reg/rect and see if you can narrow down the problem.
_________________
MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball
