Sand is tough on those small bore motors. When they work that hard they need lots of oil because they get thirsty. Even my kids super minis I ran a 24:1 mix for Moto because the motor would just be screaming all the time. Also a little fatter main jet on the top when running sand tracks.
Open her up, take some pics and let's see what's happening or happened.
Open her up, take some pics and let's see what's happening or happened.