aprilia sr50 loud exhaust

Could someone please help, i have a 2004 aprilia sr50 ditech, my exhaust has recently gone really loud and it all seems tightened, i dont know what this could be, any advice would be much appreciated, thanks

 

Run it up, put your finger over the end and see where it's blowing from.

 

Could be a multitude of things: Small hole/crack, blown gasket, or no gasket and the exhaust sealant has worn away etc...