from Murph's site:
Remove the four allen bolts holding the rear brake assembly to the bike.
No need to disconnect any hydraulics.
Remove the cotter pin holding the rear brake master cylinder rod.
Remove the rod.
Remove the U shaped adjusting arm.
Do not remove the two brake rod nuts
Take a grinder (I used a drill with a grinding wheel) and grind off 1/4" of the rod. This is about all of the half threads.
Run the two nuts back down to repair any goobered up threads from your grinding.
Reposition the brake rod to the middle setting.
Reinstall everything.
Adjust the brake light switch, which may require bending the spring.
Go for a ride!