different whine than most ?

[starvy40]

I have a 2006 nomad, the other day I pulled up to a stop light and heard this loud whinning sound, wasnt sure if it was a the cars around me or who it was so I shut my bike off and it was me. When I started it up again the sound was gone. today I was riding and I heard the sound again, I pulled over and listened to it, it sounds like gears whinning in the engine. I turned it off, and when starting it up it was once again gone. what in the heck ? it's a pretty scarey sound for it to go away after turning off and re-starting. the fan was not on either time.