The Hits Keep Coming!!!!

Okay,
So did all the Christmas upgrades, rebuilt transmission after Christmas upgrades, got the machine running good and found the factory swing arm was broke (again) in three different spots. Ordered new one. Reinstalled today.
Boys had a blast, ran great no back firing or sputter, other than needing a new chain, because I have it tightened all the way and it still appears a little loose.
So the boys take it out and after a few hours they bring it home, and there is a noticeable "whining" noise coming from the engine area. Sounds almost like a turbo whining when the throttle is applied.
Any idea what this might be? I am guessing something to do with the clutch/belt, CVT.
Have you experienced this? How much MORE damage has been done?
Almost ready to cut my loses and sell this thing. I have $800.00 dollars in this thing since the simple tire/wheel, intake upgrade which was over $600.00. So I have put $1400.00 dollars in this machine in the last month and things are still snow balling.
PLEASE HELP, really do not want t get rid of it because the kids love it, but this is getting crazy…..Thanks in advance
D