ok i have a 2004 90cc sportsman it is acting crazy. if i hold my hand over the back of the exhaust it will fire up and kinda idle but die out well i pulled the exhaust off it does the same thing but if the exhaust is hooked up it does nothing. even with starting fluid. im guessing worn rings,,cranks seals or reeds???? please help kids bugging me to death to ride..

 

i had a stuck ring on the piston and a lower crank seal out.