About a week ago while I was riding my gauge cluster went out and the bike started to jerk and make a noise as if i was stalling and then the bike just shut off at about 25MPH. The bike then would not start back up at all it would just crank and then sometimes when I turned the key the gauge cluster wouldnt even come on. I put power to the bike with a battery charger and the bike would start no problem but as soon as I would take the battery charger away the bike would shut off again. When I tested the battery it was reading at about 9volts and its a 12 volt battery. I called some local Bike Shops and talked to some friends in my area and they all said I need a new battery...I bought the brand new Yamaha battery, charged it overnight, hooked it up to the bike and the bike turned on and ran fine. I drove it for about 60 miles over a 3 or 4 day period and it did the exact same thing again and it seems like everyone I ask is just totally dumb founded, If anyone has any ideas or knows how to fix this or what it could I would GREATLY appreciate it.

Thank You.