The lights on my XJ700 are dimming when the rpms get low, and they also dim when I hit the brakes (brake lights draining system).
What is usually the first part to trouble shoot in a motorcycle charging system?
I see oem parts like a stator - $354, a rotor $376.
I see universal parts like a stator - $133-187, rectifier/regulator $70-132.
Well worth it to go through all your connections and clean them. It doesn't take much in the way of a poor connection to cause the kind of thing you're seeing.
Systematically go through one by one, cleaning with emery cloth.
It could be other things but until you know your wiring is good you will be hard pressed to solve it.
Jim
I would use a volt meter to make sure the charging system is working or not. At idle you should be getting more than 14 volts but not more than high 14s when you rev. the motor. You can measure this right at the battery terminals. Especially check the connections to the regulator and alternator. A wiring diagram will help you greatly. These sites will also help:
http://www.geocities.com/MotorCity/Speedway/7795/http://members.tripod.com/dave_jack/id47.htm