Do you have the stator connected for single output or are you running 100w AC and 100w DC? If you've got an AC/DC system it sounds like you need to float the AC ground. In other words you need to isolate the AC ground from the frame ground.
XR650R Plated Supermoto
XR628R Plated and highly modified
CR500R Still rips after all these beers
RZ350L Kenny Roberts Special
"If it's hard to do, you're probably doing it wrong."