I just bought a 2003 Yamaha r6. A month ago i bought a new battery for it, the bike sat at the house for a month no one rode it... Today I charged the battery three times, and the battery is only a month old.... The bike would run for 20 minutes then die... My buddy said its got to be the charging system... What parts do I need to buy in order to keep my bike running without killing my batter?