03 kodiak 400 started to jerk when you take off. Belt is good and all sliders are greased as they should be. It's like giving it gas an throwing it it gear. Does it in 2 &4wd

 

Are you sure the belt is good? They sometimes do this when the bike has stood a long time and the belt "sets" into the shape it was when stood, when idling it tries to get back to that shape and alters the pulleys, when you feed in the power the belt sort of jumps, then the tension returns everything to normal until the power is off again. They also do it if the belt is stretched. I would fit a new belt anyway, they are not that expensive.