Motorcycle Repair: charging system, circut breaker, voltage regulators

Question
Hello ,I have a 92 ultra classic Iam a auto technician and know how to check my system I am getting 60ac amps at 3 grand and also have tryed 2 voltage regulators the problem I have is when you first start the bike my gauge reads 14 volts (with head lamp and tail lamps only) but after about 15 min of ride time volt gauge drops to 13 volts (which its still charging ok)but if I come to a stop and just idle the volt gauge goes to 10 volts and if I hit the brakes or use the turn signals it goes to about 8 volts and if the radio is playing it goes dead(only at stops) but I can back take off and it goes back up to 13 volts my local dealer sold me what was suppose to be a upgraded stator and regulator(48 amp) I had to change my main circut breaker to a 50 amp because the 30 kept triping after I installed the new system the bike idles at 950-1000 rpms and as a technician I dont feel this is working right and have traced every wire on the bike and just cant figure this problem out and I know it has to charge better at idle I also have checked all the grounds and have added extra grounds to help....local dealer keeps telling me that this year of bike the gauge is only a smart idiot light I cant see that I hope you can shed some light on this subject

Answer
First, check your voltage at the battery. At 2000 RPM you should be showing 13.5 volts or greater. Let the bike idle down and see what the voltage is at idle with everything on. Also, when you got the upgrade, did you get the rotor that goes around the stator as well?
Let me know with you find.
Mike