Hey y'all, new here. I have a 2003 sportsman 400 that idles just fine and revs up to wot in neutral with no bog, nothing! When at ,what I guess is full speed it starts slowing Down like it has a governer. As it bogs down, If I keep it at 1/4 throttle it drives slow with no problem. It has pretty good power until I get up to speed then it's all down hill from there. I've checked for vacuum leaks and checked the filter. All seems fine. I sprayed carb cleaner around the intake and air box. No headway... Anyone have a clue!?

 

Fuel pump ? pull fuel line off carb. check[safely] for steady steam of fuel while turning over? clogged screens in fuel tank, Bad gas? keep us posted