I have a 1999 Polaris XC 700(non v.e.s.) that continues to pop through the exhaust only around idle. I rebuilt the carbs,set the floats, checked the compression(which was good), and also replaced the carb grommets(cracked bad). It seems like it might be the clutch side but when i pull the plugs the look ok. Recently i put 120 miles on it cause this was the first time out this year and i thought maybe bad gas.