Motorcycle Repair: how to check a stator and rectifier, yamaha virago 250, stator

Question
Battery wont stay charged. This is on 2000,Yamaha virago 250. I unplugged the three white wires from stator and started engine, 2 wires have 12 volts and one only had 1.5 volts is good or bad. Checked rectifier with meter, one diode gets reading both direction. Which one is bad or both? Motorcycle still runs good.

Answer
Leroy, Your on the right track. The three wire usually put out the same voltage so it souds like the stator is going south on you. The rectifier on a lot of models was finned to help get rid of heat. It also changed the stator current from AC to DC to a useable voltage like 12 volts to run the system but it generated heat doing so thats why the fins. However in years of bike electricals its not suprising to see a stator take out another electrical part. Be prepared as these two parts are not cheap. Also they wont take electrical parts back after the package has been opened.