Same rattle issue here. Didn't do it right off when I installed the tensioner a couple weeks ago. Just now changed out to 20-50, no change. I now have a pan full of new $30 10-40... ::010:: Went from the loud random clack/rattle on start up to a nice quiet start with a steady rpm clack/rattle after warm-up. I can get it to rattle as low as 12-1300 rpm, but yeah, 2000 is a good, bad? and steady rattle. Gonna go ahead and order the manual one listed before they all get back-ordered too.
Oh, and while the whine is being served, my new clutch basket has a new gear whine. Love the basket's weight effect on the motor, and the whine isn't as bad as the Royal Star's was, just wasn't expecting the meshing gears to be any louder than the one that came off.