Why is my motorcycle blowing my pipes away?

I have a 1997 kawasaki vulcan 1500 classic, and for some reason ican't keep a set of pipes. The first incident was with a pair of vance and hines that came with the bike and for no reason the pipe near the front tire cracked in two. I thought maybe they are old so i bought a new set of pipes with fish tail tips 2 weeks ago, and this past weekend on a ride the bike blew the same pipe(near the front tire) in two just like before. My buddy told me that he noticed b4 the pipe blew, that there was blue flames shooting out of the pipes. B4 i waist my money on a third set of pipes what should i do?