Do you have any devices that you installed that may be left on? If your battery is fully charged it should not produce a large spark when you put jumper cables to it. First put a DC volt meter across your battery terminals when the motorcycle is running. The voltage should read 13.5 volts or higher. This is an indicator that your alternator is charging the battery correctly. If you own an in line DC amp meter put it in series with your battery and measure the amp draw when the motorcycle is off. The current should be in the milliamp range or less. If it is drawing a higher amount of current you have to check to find out what is causing the excess current draw. If the amp draw is low when the motorcycle is off remove your battery and bring your battery to an auto supply house and have them load test your battery.