QT50 gear noise / slapping

[82QT50]

Ever since iv been ridding my QT50, iv been noticing more and more through the years that the gear noise is getting worse. It seems to be getting "loose", if that makes any sense. The rear wheel has more and more play every year. With the engine off, I can move the rear wheel forward and backward a fair amount without it "engaging" in the gears. When I take off from a direct stop and just apply throttle, it will SNAP then go. *almost like theres some play in the gears thats getting looser*. Iv been having to apply throttle slower and more gradual to avoid this.

Iv looked all over to see if anyone has had similar problems.. but I cant find anything.
Could this be the clutch? It has a centrifugal clutch.. so dont those last forever?
Anyone with a PW50 dirtbike that has similar symptoms?
Thanks