Any Dirtbike/Kawasaki mechanics on here?

[MuleySniper]

This may be a simple fix I'm somewhat handy at mechanicals but this one might stump me. My kid has a nearly brand new Kawasaki kfx90 quad. He built a little jump and was hitting it pretty good. I heard something weird when he landed and heard the chain fall off.
I took it in my shop and loosened the axle to put the chain back on and re adjust the tension. Checked the fluid levels in the motor and the transmission/gearbox. He fired it right up gave it throttle and went about 2'. I gave it throttle and it just revs, no movement from the drive shaft. I thought maybe the cyntrifical clutch belt broke. I pulled the cover and both the main and secondary clutches look fine and so did the belt. I started the bike with the cover off and revved the motor and both clutches seem to engage properly. I shut it off and thought I'd better check the teeth on the rear sprocket. Pulled it off and a couple teeth were about 50% gone and the keyways on the inside of the sprocket were all fine not stripped. I can take the driveshaft and spin it with my finger easily but it feels fairly smooth and no obvious slop. Any ideas? Im open to taking it apart and diving in but if someone on here knows more about this or has any tips for me I would appreciate it. Don't really want to take it to a dealer if it is a fairly easy fix.
Thanks
MS

[Kittman]

Might check to see if there is a CVT transmission speed limiter which may need to be adjusted.

[MuleySniper]

There is a spacer that can be removed that is supposed to gain 40% more power I read on a forum. I will do that since its apart since I thought the bike was a little doggy for being a 90cc. The secondary clutch seems slightly offset to the gear drive, I'm hoping I can remove the secondary clutch and access the area behind to see if the drive axle is snapped. Weird how the bike moved a couple feet before it happened thats also why I'm puzzled but with the tires on the ground I shouldn't be able to hand turn the axle easily right? Neither clutch turns and vice versa when I spin the clutch the drive axle doesn't move. The confusing part is the offset. I'll most likely need to use an impact and pull the clutch.