1. You have a leak circuit somewhere. This is simply a low-level current drain on the battery that slowly sucks it dry. If you've had the bike on a charger, this drain would have to be bigger than the chargers capacity. Leaks can come from accessories, alarms, GPS power supplies, or other sources. The way to check is to remove the negative battery cable and place your volt-ohm meter in the current (amps) mode. With the key off, place the meters leads between the negative cable and the battery's negative terminal. The current draw should be zero, but a small drain on the order of a few milliamps is acceptable. A drain of an amp or more is reason for further investigation.