it's either the stator, or the voltage reculator/rectifier.

there's only 3 parts to the charging system, and you've already replaced one. 9 times out of 10 it's the reg/rec, but a stator is a possibilty too.

if you have access to a voltmeter, you can check the stator output and that'll let you know if it's bad or not. there's no real easy way to test a reg/rec though.