Hello I have Kawasaki 220 Bayou I have the fuel mixture screw set to 1 and 3/4 turn out it starts runs go through all gears great except when you get all the way into 5th gear at high speed it wants to act like it wants to almost fall on its face I have messed with the fuel screw I mess with the idle screw I have put in a new plug I've even went as far as putting in a new air filter if you could please help me on this I would be eternally ggrateful

 

Have you replaced the fuel filter ? I would try replacing it first .