Hissing comeing from the clutch side

[WhiteBros400ex]

I have a 450r and there seems to be a slight hissing noise coming from my clutch side.It sounds like it u where to put water on a hot motor, it sounds like that consitent(sp) but u cant really hear it over my pipe.I check the oil and it has perfect oil,It runs and shifts fine i just want to know what it is So if you can help please do.

thanks

[WhiteBros400ex]

I cant really tell if it is coming from the clutch side it seem like it might be in my motor but i know its on the side that the clutch is one.:huh :confused: