Carefull.....................................
Carefull doing this - when I first got my GS I did a service, and opened the cap on the bars, topped the fluid level up, turned the ignition on and tried to bleed the fluid through as I've often done with other non servo brakes.
It took a while for me to realise that although fluid was bleeding out of the callipers, but the levelin the reservoir wasn't going down.
The two circuits (triggering and braking) are seperate, and all I did was drain the braking circuit, necessitating the tank off again.
Good luck, but read up on it first!
Cheers,
Shadow.