Motorcycle Repair: Exhaust Problems, helicoil, exhaust pipe

Question
I have a 1975 Electric Glide Classic.  The bolt on the rear cyclinder for the the exhaust pipe has been drilled out and a helicoil inserted.  Still takes the 5/16 keeper bolt.  This is now  loose and will no longer remain tight. This is now leaking exhaust gas and burning the copper gasket.  Looking for a solution for repair.  My question is, can JB Weld be used to pluged the hole and be redrilled and tap again with the original size?  If not, do you have any suggestions?

Answer
No, you cant use JP weld. It wount last with the heat. There are two dofferent ways to repair. One is to drill the hole for a bigger bolt. Then you have to drillt he exhaust pipe hole also. The other way is to remove the head and weld the hole closes, redrill and retap for the correct bolt.
Good luck and happy riding
Mike