Noise When I Roll It Backwards

I just bought the bike, but today when i was backing up on the bike before starting it, the bike made a really quiet hum sound... when i roll it forward it was completely silent.. only does it when i backup and you cant hear it if the motor is running... does it in any gear or neutral with the clutch pulled or in neutral either way..

What do you think it could be?

IMO it's all in the chain... Rolling forward or backward changes the orientation and drag points. I bet right after you lube the chain it sounds different.

And - Make sure the chain slack adjustment is proper.

Mark

Chain or brakes dragging slightly probably.