So I bought a 95 polaris 400 explorer and guy says he just had a top end redone in it and that he was plowing his driveway way and it died I have completely rebuilt carb I have spark I have gotten to back fire real loud few time but never start checked compression with a O'Reilly rental and it says 65psi could valves needing adjusted or timing being off cause this low compression reading?

 

I don't know that machine at all but the answer is yes. Check valve adjustment is correct and while you have it at TDC on the compression stroke, (check this by the piston as well as the flywheel mark), check the cam timing mark(s) are correct. If timing is out, it must have slipped.