Your A should have a 280W output vs the standard 225W system. The field coil is wound differently with larger wire and less resistance to produce higher output. Our bikes are notorius for puny charging systems. Most times it's something simple like a bad wire, a bad rectifier leg, corroded and/or loose bullet connectors, bad igntion switch, voltage regulator, etc. Have you checked your charging voltages at the different rpm ranges? If it's up to snuff with this test then I'd speculate that you may well be overloaded.