hey guys, i just bought a 2000 f4 from a guy and he said that the bike wont charge or anything. He hooked a portable battery jumper up to the bike and it fired right up, but when i try to start the bike with a new battery i put in, nothing turns on at all. I hooked a battery charger up to it thinking the battery was dead but the charger said "check". and it wouldnt charge. Im thinking that maybe my voltage regulator is bad???? any tips help. thanks guys