Motorcycle Repair: battery charging, volt meter, ac output

Question
When at idle the volt meter reads less than 12 v. when I rev the motor the volt meter slowly climbs to about 12.5 and may stay there for awhile. Taking the bike to 3000 rpm on the highway (70 mph) the volt meter will some times go up to 14 but usually 13.5.
As soon as I slow down the volt meter drops back to 12.2 until I stop at which time it may go below 12(such as at a stop light). The bike is a 2002 FLTR with a battery about 1-1/2 years old
This really has me confused. Do you have any suggestions? The battery seems to be fully charged at all times and has never gone dead. I have had no starting issues at all.

Answer
First thing I would do is have the battery tested, to make sure its good. If its ok, then you will have to test the stator and see what the AC output is. If its to low the stator will have to be changed. If its ok then the regulator is bad
Good luck and happy riding
Mike