inner pipe/head pipe

[marius]

I had this rattle noise from what sounded like lower engine but I was told that it could be the inner pipe that came loose in the head pipes so I took them a part and found that one had come loose about 3/4 in.from the diameter where it was welded. I wondered if it can be welded back in place or it will have some long run effect. If anyone has any experience with this please let me know thanks Marius 92' Max p.s. the bike has 37k mi.