Why does your harley battery go dead after a few days?

If your battery is going flat after sitting for only a few days at idle, there can be several culprits. One is that the battery is old, and is no longer able to retain a meaningful amount of charge. Remove it, and take it to any mechanic shop to be tested. A dirty or corroded battery can also cause a "surface drain." Insure that the battery terminals are clean and free of corrosion. If the battery is not the problem, then there is an electrical fault somewhere on the machine. The procedures for testing for a circuit fault are detailed and easy to follow in your HD Service Manual. All you will need is a multimeter (which can be bought for less than 20 dollars) and some time.