8. CYLINDER HEAD/VALVES MXU 500 IRS Camshaft Support both ends of the camshaft with V- blocks and check the camshaft runout with a dial gauge. Service limit: 0.05 mm Inspect camshaft lobes for pitting/scratches/blue discoloration. Measure the cam lobe height. Service Limits: IN : 37.11 mm EX: 36.86 mm If any defects are found, replace the camshaft with a new one, then inspect lubrication system. Check the decompression system by turning the decompressor cam on the exhaust camshaft. You should be able to turn the decompressor cam clockwise smoothly, but the decompressor should not turn counterclockwise. 8-10