I have a 2005 Yamaha yfz350. The battery was replaced a month ago so I don't think that is the problem. I have to pop start it to get going. The fan won't come on so it overheats. With power on I don't get headlights, neutral light, nothing. Even after pop starting the neutral light won't come on. If it's not the battery what can it be. Please help.  

maybe you have a short somewhere... check everywhere wires are at and make sure they aren't rubbing on the frame somewhere or on anything metal... idk what else it could be... unless u hooked up the battery backwards haha  

possibly you have a blown fuse or relay or even a bad cdi.