Motorcycle Repair: Ignition modules melting, rotor coil, stator windings

Question
I have a 1980 Honda CB650C and when I removed the seat, I noticed that black tar like material was being melted out of the aluminum housings that I believe are called ignighter modules.  These are mounted back to back and are small 1.5 inch square aluminum housings with one pigtail wire set coming out of each.There are two of these. I am assuming each one is for two cylinders. Someone has told me that the rotor could cause this problem. I am assuming that the rotor or the regulator which supplies the rotor with power to regulate the magnetic strength of the rotor coil to regulate the alternator output is failing. Any thoughts of proper resistance of the rotor windings to rule out the rotor as the source of the problem. I will check the resistance of the winding and the resistance of the winding to ground for a shorted winding. I have a 1000 volt Megometer for checking motor windings.
Could I use it to check the windings for proper insulation resistance. I heard sometimes a hot rotor will show a different reading than a cold one. I would disconnect the rotor from the rest of the electrics before using the Megommeter. Any help would be appreciated as I am new to this motorcycle.

Answer
Tanya, First, the ignition modules (spark units) often show signs of gooey tar/black stuff coming out of them now. The parts are interchangeable with many models and one company is making reproductions of them, however they are expensive. The ignition modules really don't have anything to do with the charging system, other than perhaps during an over-voltage situation that might cause harm to them.

GO to this site for more specifics on the charging system issues..

http://www.electrosport.com/technical-resources/library/known-issues/street_4325...

You can check the stator windings for electrical breakdown, but an ohm meter will usually suffice. Follow the link above and choose the troubleshooting tree for more detailed system analysis steps.

Make sure that the brushes are long enough to contact the rotor face all the time, then check the stator wiring connector for signs of damage. Check the rotor specs as above, if all else checks out, then the reg-rectifier is probably dying/dead.

Bill Silver