I need help my bike starts but wen i pull throttle it doesnt move only revs

[Kbg]

So I got a trailmaster mb200 I recently put the stage 1 perf kit upgraded jet air filter and exhaust . I lightly laid it down while riding nothing even serious but now it starts but when I give it throttle it doesn't move but the engine revs? The linkage and ect. Is intact I know I need to inspect the torque converter over everything looks in place from the outside.Ima try to post a video here wen I get a chance any ideas lol

 

[sparkwizard]

Is the chain still on the rear wheel sprocket?

 

[Kbg]

Yeah it is lol I just went and started it and it ran fine so ima just ride it over the next few days to see if there's anymore problems I'm thinking the belt is Hella worn but still worries me not trying to break down

 

[SAS289]

Only time I had something similar was when a new rider was on my "down tuned" Coleman. For some reason he kept going on and off the throttle repeatedly at slower speeds. The driver got so hot that it would not engage. I wanted to service it but didn't bring any dry lube. After letting it cool off for an hour or so it worked well the rest of the day, like nothing ever happened. Looked good when I serviced it.

 

[RobertC]

Only time I had something similar was when a new rider was on my "down tuned" Coleman. For some reason he kept going on and off the throttle repeatedly at slower speeds. The driver got so hot that it would not engage. I wanted to service it but didn't bring any dry lube. After letting it cool off for an hour or so it worked well the rest of the day, like nothing ever happened. Looked good when I serviced it.

I like the sound of that, and was wondering what would make the belt slip, or not engage.
I was thinking moisture, but @SAS289 , your explanation sounds more logical.