A brief explanation of electricals:
The stator is a cluster of copper coils that is attached to your crankshaft. Surrounding them is a stationary, powerful, magnet. As the engine spins, electrical current is created in the coils, due to the powerful magnetic field. The type of current produced in the stator is AC voltage, in three phases (signals) and is completely unsuitable for use in a motorcycle. To make it into something useful, a Regulator Rectifier is used.
A Regulator Rectifier, often called a reg/rec is used to convert the AC voltage created by the stator into useful DC voltage. The stator must always be making MORE THAN 12V, so that means the Regulator part of the reg/rec regulates the voltage to a constant 14.4V by dumping excess voltage to the chassis. The rectifier part of the reg/rec is what does the conversion from AC to DC by joining the 3 phases of AC to a single DC signal.
Some notes about Hyosung: The reg/rec used in most (all?) Hyosung motorbikes is based on 'diodes' that are of poor quality. They perish easily. The standard reg/rec is not reliable and will fail quickly.
Testing of electrical components:
To test your stator, you will need to have a multimeter. You will also need to locate the connector on the bike from the stator to the reg/rec. It is a three pin connector with three yellow wires. These wires are identical and it does not matter which is what. They're the same. Lets call those pins A, B & C.
1. Set your multimeter to AC voltage.
2. Disconnect the stator from the reg/rec.
3. Start your motorcycle in neutral.
4. Rev the engine to 5,000 RPM.
5. Measure the voltage on the engine side across all combinations of the three pins A to B, B to C and A to C.
6. They must all output a roughly equal voltage.
7. The voltage must be close to 70VAC.
To test the reg/rec:
1. Set your multimeter to DC voltage.
2. Locate the two pin connector leaving the reg/rec. This wire is what charges your battery.
3. Measure the output from the two pin connector leaving the reg/rec.
4. It should be above 13V, preferably above 13.5V.
This is a reg/rec:
This is a stator:
I hope this helps,