Here is the Service Manual for the 2017 Cub Cadet Challenger 750 and it is compatible with the Hisun 500/700 manual as well.
I paid $45 for it but I want to share with everyone because they are a pain in the ass to find.
Enjoy!
17-18_HS500-7_SMAN_PDF.pdf
For anyone looking for this information in the future I did find the Valve clearance specs for adjusting them.
Intake Valves-.08-.12mm
Exhaust Valves-.12-.15mm
Make sure you are at TDC when making the adjustments.