Backfiring out carb and wont run right

In no particular order

vacuum leak

carb AFU IE gummy, floats too high / flooding, dirt in needles seats/ pump problems

timing / ignition. Use a piston stop. Check your timing mark. Check that the advance mechanism is working and the timing is where you think

CHECK THE PLUG WIRES

Valve hung open, IE bent valve, damaged valve gear mis adjusted valve, etc