I have an 87 TW with a charging problem. I haven't used it much in years but just recently started making it road worthy again. I put a new battery in today and its not charging. When running, the dash lights and tail light are on solid, but the headlight goes brighter and dimmer with rpm's. I have around 12.7 volts with key off, and it drops to around 12.4 when the lights are on/running. Does this sound like a bad regulator? Any other tests than can be done? Thanks!