I have a 2009 Arctic Cat and while in neutral when I rev it up it fluctuates up and down. It has fuel infection and also there is a slight knock coming from the clutch side I know this is probably the wrong place to be asking these questions and I don't mean to be off topic but can anyone help.

 

Fuel infection? have you tryed running a injector cleaner through it? Also i would pull your clutch cover off and blow everything out. I do mine once a year and a lot of dust comes out..