Go that little bit further and pull the reeds out maybe theres a read seal split or gone completely and wile your at it check the gaskets in the carb (all of them).
if you dont find a stuck or damaged reed or air leak on inlet side,
pull the pullstart & flywheel off & inspect for any oil leaks from the crankseals seals tend to shrink or breakdown faster when the bike has been stores & they dry out