I have a Kawasaki VN88, 1500, Battery is not charging, new battery installed and charged and will start engine but after awhile I cannot start the motor because the battery is dead. Battery is not re-charging.

Its either the alternator or the voltage regulator that has packed up.
Unplug the the cable from the regulator and using a multimeter to read ohms measure between all the 3 yellow wires, they should be between 0.3 and 0.5 ohms.
If ok then its probably the regulator.

Hi and welcome to the site,

Almost always, your described problem would most likely indicate a faulty rectifier / regulator combo.  Other possibilities are loose or corroded terminals on the connectors from the stator to the regulator (3 yellow wires) or the output wire of the regulator to the battery + line.

The connectors / terminals could be visually inspected and thereafter cleaned. The regulator could be checked with a voltmeter. At idling, battery voltage should be arounf 12.7 + while would go up to 14.5 as the RPM is increased.

Would appreciate updates.

Good luck and thank you for using FixYa.