Get a DC Volt meter, and with the bike not running check battery Voltage, than turn on tender and check voltage at battery. Remove tender and start the bike and check voltage. With the bike running and the tender on the bike the voltage should be almost 14 volts. With the battery by itself the voltage should be in the mid 13s. While the bike is running it the voltage is below 13, I would replace the voltage regulator on the bike. If while tender is on battery if the voltage is below the mid 13s, replace the tender. If the battery is in the low 13s, get it load tested. If it doesn't pass it replace battery.REMEMBER, a tender is NOT a charger. a new battery needs to be trickle charged at least 12 hrs before you put in the bike to reach full charge. and even then it still may not be any good.
