Back Muffler

Question on welding a muffler on a motorcycle yet …?
The nuts holding my muffler on the engine loose, allowing the muffler strong enough to vibrate out of the pins was mounted in the engine. Now, to my silent again, I do not weld the bolts on the engine or just my muffler can be welded directly to the engine. OA way, my question is: If I make a barrier thickness of fiberglass insulation, welding or blanket between my welder and all the other parts of the bike (except for the small to be welded), otherwise you should remove the engine and drain for welding course my new muffler?
None of these soldiers incorrect parameter. No work … If possible, try to break or broken plugs and easy to both Back holes. If the collar on the tube is damaged. necklaces can be found by dividing the pipe diametor can be used in the engine cycle or auto parts store. If can not make the correction to the head and repair garage can do the job
Lancer ’08 Magnaflow Axle-Back muffler