What is the cause of a rattling noise on your 2002 Kawasaki Vulcan 800 during engine warm-up and low torque acceleration which seems to originate near the where the exhaust pipe meets the engine?

had the same problem with mine.If you take off the exhaust pipe you will see that inside the pipe at about 2 inch from the top the inner pipe is cracked.If you're lucky and it's not too far down you will be able to get it weld(MIG).Mine was almost a complete circular crack of the inner pipe and not accessible...had to buy new set of exhaust!! Good Luck JM