What controls how much charge a battery is given on a 1981 Honda CB900 Custom Charging Sytem

[unicowboy]

I have a new battery in my bike and it got boiled dry with an overcharge....like to know what component in the circuit would let that happen. Would it be the Voltage Regulator...as IC other switches and parts connected to the system.

[surplusdealdude]

Yes, it's the voltage regulator.  Nowadays, they're usually incorporated into the alternator.