Motorcycle Repair: electrics and battery problem, kawasaki gpz500s, haynes books

Question
I know you prefer hondas but you might be able to help. I have an 87 kawasaki gpz500s. The problem being the battery is not getting charged when the lights are on. with lights off and at 4 -6 k revs the current at the battery is about 12.7 volts, enought to maintain the charge. With lights on this drops down to 10.45 - 11.00 volts, therefore draining the battery and after a long drive making it impossible to start without bumping it. the level in the battery is good and if chaged off the bike it will hold a charge. Any suggestions as to what to look at, in both my Clymer and Haynes books there is no suggstion as to what the cause might be.
In advance of your time, i thank you for your help.
Many Regards
Glenn Collins.

Answer
Glenn.... Go to www.electrexusa.com and download the trouble shooting manual in pdf format for free. Sounds like your voltage regulator is not doing its job. Sometimes the stator will ground out a circuit and/or the wiring connections get corroded, overheated and burn open.
Check ALL ground paths for the charging system, as well.

Be sure that the battery will take a full charge, however. If it is over 2 years old, replace it. Just a voltage check is not enough to analyze the battery condition. Find a shop that has a load tester to see if it will really hold the charge.

After that, you can follow the troubleshooting chart and determine what is going on there. Charging system should be kicking out 13.5-14v volts most of the time to keep the battery at 13.2 full charge.

Bill Silver
Bill Silver