This can be caused by "diffing out" your tires or holding the throttle open while one

Camlocks: Better stem stability

and swapping gritty

ARRMA ARA330608 HD Shock Rod End and Spring Cup Set (2 Pair)

Pro-Line 1/4 Dunlop Geomax MX14 V2 Bead CR4 Rear Mounted Tires Losi Promoto MX Mini Drag Parts This can be caused by1 4 Dunlop Geomax MX14 V2 Bead CR4 Rear Tire MTD Black Bullyspoke: MX TIRE FEATURES Officially Licensed by Dunlop Motorcycle Tires The Same Tread Design Used by Pro Motocross Riders V Block, Scoop Shaped Tread Lugs Ideal for Mud, Sand, and Loose Dirt Exacting Scale Details Unmatched Forward Traction and Handling Pre mounted to Bullyspoke V2 Bead Wheels Made and Assembled in the USA WHEEL FEATURES Thicker Spokes for Increased Durability Narrow Profile