S
I am pretty sure this rattling noise is in the clutch, ive had it on my 2015 800 rush and now on my 2019 850 indy, what it is the clutch tower buttons have to much clearance, should be .001 to .002 . Mine were at .006 to .008. To prove this was the noise I put small peicies of shim stock between the tower buttons and the towers, wedged them in there tight, noise went away,this is just a test, clutch must be disassembled and shims put behind tower buttons to get proper clearance, I think Polaris leaves them on the loose side in assembly to prevent possible binding.When you let off on the throttle it takes pressure off the tower buttons and you get the rattle, also at idle when there is no pressure on the tower to button clearance. TRY THIS TEST, JUST LEAVE IT IDLE THOUGH,DONT TOUCH THE THROTTLE.
