2008 Yamaha Raptor 250SE / 250SE2 Factory Service Manual, Page 126Get this manual
CYLINDER HEAD
CHECKING THE TIMING CHAIN GUIDES The following procedure applies to the camshaft sprockets and timing chain guides1Check: Timing chain DamagestiffnessReplace the timing chain and camshaft sprocket and crankshaft sprocket as set
2Check: Camshaft sprocket More than 14 tooth wearReplace the timing chain and camshaft sprocket and crankshaft sprocket as set14 tooth Correct Timing chain Camshaft sprocket