2008 Polaris ATV Sportsman 300 400 H.O. Service Manual, Page 31Get this manual
MAINTENANCE Valve Clearance (Sportsman 400 H.O
Inspect and adjust valve clearance while the engine is cold and the piston is positioned at Top Dead Center (TDC) on the compression stroke12Remove the fuel tank to access the valve coverRemove the spark plug high tension lead (A) and remove the spark plug (B)CAUTION: Place clean shop towel into the spark plug cavity to prevent dirt from entering5VERIFY the following: "T" Mark on flywheel is aligned with the projection in the timing hole of the recoil housing The camshaft sprocket locating pin should be facing upward, directly in line with the crankshaft to camshaft center line as shown belowThe camshaft lobes should be pointing downward Rotate engine slowly by turning the flywheel, watching the intake valve(s) open and closeSprocket Alignment pin facing up
B 3Remove valve cover bolts, valve cover (C) and gasketCrankshaft-to-Camshaft Centerline
NOTE: It may be necessary to tap cover lightly with soft-faced hammer to loosen it from the cylinder head4Remove the timing inspection plug and rotate the crankshaft until the "T" (Top Dead Center) timing mark on the flywheel is aligned with the mark in the timing inspection window of the recoil housing