[RenegadeRider]

 

[99MXZ600]

How do the clutch surfaces where the belt rides look? Maybe there's something on them making the belt slip just enough to make that noise. Maybe the dealer used some type of cleaner on them that left a residue. I'd try cleaning them myself and see if it makes a difference. Good luck and ride SAFE.

 

[FlipMode]

Do you think this sounds is comming from the engine or the clutch?

Try removing the clutch guard (that is if you didn't remove the plastic shield off the clutch guard) and take a rip on the sled, see if it gets louder if it does then we can narrow it down to it possibly being the clutch.
While you are there just do a quick visual to see if the PTO seal looks good as well.