1993 GSPD with about 85,000 KM (50,000 miles). I just replaced the alternator rotor (for the third time). Prior to and after rotor replacement, I noticed that in the morning I start it up and as I drive the (aftermarket) voltmeter jumps back and forth indicating between 13 and 14.5 volts. It jumps quite a bit which I think is fine - indicates the alternator is putting out power and the regulator cuts in and out as required. After about 10 minutes of riding, the voltmeter needle stabilizes at 13 V. This generally corresponds with my arrival at a freeway on my moring commute. The needle stays pretty much rock solid on my 15 minute highway commute (4500 to 5000 RPM). When I get back into city traffic, stopping for lights,etc, lower RPMs (idle to 4000), the volt meter is indicating only about 11 volts. My total commute time is about 30 -40 minutes. My battery is about 1 yr old and I haven't had a problem with it dying. Could it be a regulator issue that only happens when the bike gets warm? I just added some water to the battery this morning and will keep an eye on it to see if its boiling the acid/water out. My concern is that perhaps my alternator is running full out all the time (once the engine warms up) and that is causing the premature failure of the rotor. I've had the bike since it had about 15,000 km on it (one year old). As stated, I replaced the battery last year (first time) and I've smoked three rotors. Could my regulator or Diode Board be faulty? Currently (pardon the pun), I'm not running any extra electrical stuff (I've got heated grips, vest, radar detector and aux lights but none of these have been switched on since I blew the last rotor and really started paying attention to what is going on). I also haven't done the brushes yet but anticipate updating them before fall/before my next little trip. Any help appreciated. Thanks.