kohler popping

[blackheart]

OK I have a 13 HP cv13 kohler. The original reason it needed repairs is cause the balancing rod end broke off and the oil pressure drop and the connecting rod had wear in it. After all that was replaced and the engine was cleaned out the lifters locked up and eat the lobs off the cam. So this was fixed. Different lifters and cam. Now there is a popping sound coming from the Carb ( like its backfiring). Removed the valve cover and the lifters have not locked up this time but I still can't figure out why its popping like this. Any help would be greatly appreciated .