I have a 2003 Yamaha FZS600 that lately started to drain the battery while it's not in use for 2-3 days. I bought the battery in this year's February and if I charge it it does its job. Yesterday I wasn't able to start the motorcycle normally again so I jumpstarted it (works & goes perfectly that way). After a few miles I noticed that instruments are going off and on again. The headlight stays on, engine runs perfectly though. When I hit the PASS light or switch on and off the headlights it does that almost everytime too. Any ideas where to start checking things?