alternator rotor

[suzukiintruder411]

is the rotor for a 1972 CB 750 magnetized only when there is current and can a rotor break down

[Re-run]

Yes, it is an electro magnet and the insulation on the windings can break down, though it is not common unless some sort of damage occurred to the insulation.

[Lucky 1]

You can do the check that is in the workshop manual or go online to http://www.youtube.com/watch?v=-8BS1OoiEgI&feature=relmfu
Randy's cycle service, alternator check and he has a video on how to check your rotor and stator.

Make sure to notice that the digital Volt ohmmeter is set on 200 ohms.