when im driving my 2003 honda foreman the sound that comes out the exhaust is like a hissing like air coming out of a ball
then my 4 wheeler starts to decelerate and i have to press the gas several times for it to accelerate without the hissing sound. any suggestions

 

Water in the baffle,does your bike have a drain plug on the bottom of your baffle?

 

Are you sure the noise is from the exhaust? Ive heard the same hissing from carbs which have the mixture screw backed out too far, or missing. It would also cause the need to gas it, and the hiss going away.
Check the mixture screw.

 

ok thanks