I put in a brand new battery and just to be sure it was fully charged, I hooked it up to my 6V battery charger and trickle charger combination. The red light was on for about 5 minutes, indicating charge mode, then it turned green, indicating float (not charging any more).

Installed it.

Voltage across the battery with it connected, bike not running, headlight in either lo beam or hi beam measures 5.32 volts. Horn still only makes a faint clicking sound without the bike running.

Bike running - 8.2 volts across the battery. Horn works even better than it did with the old battery; a nice, clear tone (I guess it was just a hair muddy sounding before, although I didn't notice it.

Headlights in either the Lo beam or Hi beam still kills the motor.