problem with my 2000 gsf bandit 600
 

I just got this bike about 2 months ago and i have had no problems until now... it rides fine and shifts good.. but im hearing a weird sound when i hit 5000 rpm. its almost like a buzzing sound coming from the motor. I work as a diesel mechanic and i can fix most anything i get, but this is the first bike ive ever had to work on and i was hoping this was a common issue for this type of bike and maybe someone could lead me in the right direction. if you can help i'd really appreciate it.