First, check your carb with a dial caliper or electronic caliper and see if you have the .575 bore carb or the .615 bore carb. Some predators came with a Rui*ing RATO carb on them, which was the small .575 venturi bore and .700 throttle bore compared to the RUI*ING that came on the clones with a .615 venturi bore and .750 throttle bore. The smaller carb would use smaller jet sizes to get it working properly compared to the bigger ones. Find an etube that has 20 holes in the top and 4 holes in the bottom, and start with a .037 main and .024 low speed jet and work your way up from there. With aftermarket filter, the .036 is likely going to be too lean anyways. Read the spark plug to tell you if your rich or lean, and adjust from there. Needs to be done on the track, not with kart on a stand.
