I have a 2005 suzuki ozark and I am getting alot of valve chatter at high rpm and when I am accelerating up hill. I had the valves adjusted but it still does it, anyone have any suggestions?

Also ozarks have a carb drain screw and a hose that runs behind the motor to drain the carb and for some reason it leaks gas out that tube all the time. I have tightened the drain screw as tight as possible but it still drips out that hose when the atv is running. Any help on this would also be appreciated.