I just worked on one of these machines for a customer of mine. I completely rebuilt the carb, sometimes at idle it would load up like it was running too rich. The another issue he was having was it would suddenly stall when you came to an idle then start right back up. Both of these problems are caused by a bad fuel valve, the vacuum diaphragm gets deteriorated and starts pulling fuel through the vacuum hose or doesn't flow fuel correctly. I've had 2 customers with 2 different Suzuki model ATV's with the same issues a bad fuel valve assembly. There are no rebuild kits and the oem valves are much higher quality than after markets so just spend the money and put a good one on it.