2008 Yamaha Raptor 250SE / 250SE2 Factory Service Manual, Page 143Get this manual
VALVES AND VALVE SPRINGS
CHECKING THE VALVE SPRINGS The following procedure applies to all of the valve springs1Measure: Valve spring free length Out of specificationReplace the valve springInner spring Free length (intake) 36.17 mm (1.42 in) Free length (exhaust) 36.17 mm (1.42 in) Outer spring Free length (intake) 36.63 mm (1.44 in) Free length (exhaust) 36.63 mm (1.44 in)