Rolled past 250 miles the other day. Decided I would do an oil change (Mobil 1 0w-40) and check the valves. Valve check was super easy. Remove seat, remove black plastic side panels, remove gas cap and plastic tank cover. Then unplug wire harness and undo screw clamp on fuel hose. Remove one allen head bolt and tank slides right out. Cover tray between fuel tank bottom and top of engine pops right out. Remove plug on left hand side of motor to set piston on top dead center. I carefully used a bamboo stick to confirm top dead center. {Piston all the way up and rocker arms with free play. I used 0w-40 Mobil because I had some, use it in my wife's turbo Subaru. Valves were with in specs so no adjustment was necessary. Also pulled and cleaned the air filter. For me it seemed pretty easy to undo the clamps on the duct for and aft of the filter. Pull the housing out of the wheel well and remove the filter disconnected from the atv. I have heard some on the Arctic Cat forum pure cuss this filter housing access but seemed fairly easy for me the way I did it.