1998-2004 Honda Foreman 450 factory service manual, Page 157Get this manual
CYLINDER HEADCYLINDERPISTON Align the punch mark on the cam sprocket with the index mark on the crankcase, then remove the camshaft
CAM CHAIN TENSIONER REMOVAL
Remove the mainshaft bearing retainer bolts and bearing retainercam chain tensioner assemblyRemove the oil pump (page 4-8) and cam chain slipper
INSPECTION
Camshaft
Using micrometer, measure the height of each cam lobe and inspect it for wear or damageSERVICE LIMITS;
36.25 mm (1.427 in) 36.10 mm (1 .421 in)
Turn the camshaft bearing outer race with your fingerThe bearing should be turn smoothly and quietlyAlso check that the bearing inner race fits tightly on the camshaftReplace the camshaft as an assembly, if the races do not turn smoothly, quietly, or if they fit loosely on the camshaftCheck the decompressor cam operationLook at the base of the exhaust lobePress on the decompressor cam as shownAs you press on one side, the decompressor cam should lock above the exhaust baseAs you press on the other side, the decompressor lobe should be depressed below the exhaust base