if the atv sat for over a yr, and there was moisture in the oil /motor, or?? its possible a one way bears got rusty and is now again on its way out
same can be said for dry CV joints
simple thing to check on CV joints is, get up close and personal with the boots, look for any tears, if so, they need to be fixed, and that could be your issue's
if you DON"T see any tears or??
squeeze then and see if they squeeze or is like a balloon and full of air, and doesn't come out like, they should be TIGHT, so they work to keep water and crap out, if NOT, they again could be bad or just need new packing of grease?/
its very hard to tell what something is by sound, when your NOT there to hear it
you can get a service manual(NOT an owners manual)
either BUY a hard copy, or there are free online down load ones
and last, if this atv SAT for over a YR, I HOPE you did it and yourself a huge favor, and did some basic things to it before running it
like changing ALL fluids, oil,oil filter, clean and or relplace the Air filter!
drain and replace the diff fluids, and drained any OLD fuel in the tank, and made sure the tank is clean inside
and IF liquid cooled, you maybe want to drain and flush the coolant and start with new coolant too
a new spark plug isn';t a bad idea either!
skipping these things can be a lot of unneeded issue's to come for you!
just good advice here, things that sit, and then run more, can mix dirt and crap that settled into places it shouldn't be!
