Exhaust groan/rattle, help!

[peckgsx05]

My 1990 GSX had one problem that I cannot figure out. I am getting this wierd exhaust groan/rattle from 3500 RPM all the way to redline. I originally thought it was my 14b exhaust housing which was cracked, but I replaced it and it still does the same thing. I pulled on the throttle and listened a little closer and it seems to be coming from near the timing belt or right under the timing belt. Anyone have any idea? i'm pretty sure it's exhaust related, but wanted to get some ideas before having my local shop diagnose it.

 

[95blackGsTurbo]

Did you do a boost leak test to see if there is an exhaust leak? Are you sure your timing is on and hasn't jumped at all?

 

[destruckeclipse]

My stock cat does that. It was replaced it with a high flow and now no problems.

 

[Da Dymer]

it might possibly be something as simple as a loose heat shield on the exhaust....that will cause a rattle