Motorcycle Repair: 1974 Honda 550 four, honda 550 four, voltage reg

My battery was not charging,so i replaced the rectifier and voltage regulator.Now the battery will charge.But heres the tricky part i set the voltage reg. at 14.5v at 2000 rpm with the headlight off.Stator will put out charge but if i turn on headlight it will not charge unless i rev the engine to 4000 rpm. also it drops the voltage reg.down to 11.5v. I think that maybe the stator is going bad but im not sure any help would be appreciated. Thank you ..

Bob, those alternators don't put out a lot of current.  The regulator is normally set to keep the battery at 13.5 volts when the engine is revved between 3000 - 4000 rpm with the headlight on.  If you step on the brake, the voltage will drop below 12.5 volts.  This test has to be run once the battery has been fully charged.  If the battery is low, the alternator won't keep up.