just change the spark plug. the spark plug is the thing attacked to the biggest wire under your foot rest. pull on it the white thing that was attached to it is your spark plug. unscrewwy it. go to auto parts store say hay i need one like this ,don't get auto lite plugs, re screwwy. ride. simple? sorry i suck at explaining things. it is easier than it sounds.
as for the noise it hates you. ok seriously what type of noise? i did you take off the top cover thing on the air filter? umm parts diagram to help explain this:S.