Fuel tank shaked a decelerate

[moto]

I read one comment where is expain that exhaust is also one reason what make shaking on the bike.
I have Drifter oem exhaust but I one month ago loosen exhaust silencer because I need to change rear brake pads.
Then I connected silencer back very tight. I dont know is this is one reason for shaking.

[Troll]

Should be 2 rubber pads on the frame and 2 rubber mounts on the neck, and one bolt through a rubber mount on the back

[moto]

How many bolts a tank is connected, one is under the seat, is there any bolts a front of the tank?

[CDNRatMan]

Tank is loose

[moto]

I noticed that fuel tank shaked very much when I decelerate.
Is this normal, or do I have to check tank connections?