How old is your battery? They dont last very long, so I would first charge up the battery, then if you have a voltage meter, put the leads on the battery while it´s running. it should show about 12 to 13. Then rev it up to about 500 rpm´s, if the meter doesn´t go up to at least 14, then it´s a problem with your charging system. If it does go up then it´s either your battery or you should get a battery tender. If you don´t ride your bike ALL the time, then it´s a good idea to get one. So try all that and let me know how it goes.