I have an 04 Suzuki Eiger that had many of the common carb problems. Most noted was back firing through carb. I have tried cleaning and rejetting with no success. Set valves which were already nearly spot on. I just installed a knock off Chinese carb which matches the original exactly. Atv runs great now with no spitting and sputtering. Only issue is atv starts with no choke even when cold. The choke turns off engine no matter hot or cold Also there is the smallest flat spot between idle and half throttle. My experience tells me the pilot jet is too rich. Spark plug doesn't look black. Since it is 100 times better than before is there anything to worry about. I searched the threads and couldn't find much info. Any help would be appreciated.

 

If the spark plug doesn't look black I wouldn't worry about it. Some bikes only need choke in really cold weather, the Honda 300 was one, Eigers were not, they seem to always need a bit, but if it runs OK and doesn't soot the plug, it may be slightly thirstier, but otherwise, a slightly rich mixture won't make much difference.