2005 Yamaha F90TR 90HP Outboards Factory Service Manual, Page 94Get this manual
Cylinder head
S60C5450
Valve stem diameter b: Intake: 5.9755.990 mm (0.23520.2358 in) Exhaust: 5.9605.975 mm (0.23460.2352 in) 4Measure the valve stem runoutReplace if above specification
Valve guide inside diameter a: Intake and exhaust: 6.0006.018 mm (0.23620.2369 in) 2Calculate the valve stem-to-valve guide clearance as followsReplace the valve guide if out of specificationValve stem-to-valve guide clearancevalve guide inside diameter valve stem diameter: Intake: 0.0100.043 mm (0.00040.0017 in) Exhaust: 0.0250.058 mm (0.00100.0023 in)