My 1985 ATC runs great. But when you turn the wheel in any direction there is a loud popping cracking noise and the rear wheels bind. Any help would be appreciated

 

Sounds like a rear axle bearing. does it have a swing arm or rigid frame? if it has a swing arm the bearings in that could be bad too. also check for a cracked frame. also could be the chain, if its chain drive, make sure its adjusted right. and if its shaft drive could be shaft joint bad. just gonna have to look it over very closely.