I have a 2006 RG. Last weekend I could hear what sounded like the primary chain hitting inside the primary. I limped the bike back home, put it up on the table and opened the primary inspection cover. Chain was correct tension so I pulled the primary cover off and found the compensator spring pack was torn open and the plates had been sticking out and hitting the inside of the primary case.
Of course, none of the local dealers stock it so it took a week to order a new one.
I had recently replaced the original spring pack about 6K miles ago because it was rattling.