Yamaha F150B Service Manual

Also see for F150B: Owner's manual Service manual Owner's manual

7-40Cylinder head012345678910AChecking the valve guideBefore checking the valve guides, make surethat the valve stem diameter is within specifi-cation.1. Measure the valve guide inside diametera.2. Calculate the valve stem-to-valve guideclearance as follows. Replace the valveguide if out of specification.Replacing the valve guideAfter replacing a valve guide, check the valveseat contact area.1. Remove the valve guide a using thespecial service tool b from the combus-tion chamber side.2. Install a new valve guide c using thespecial service tool b from the camshaftside until the valve guide installer dcontacts the cylinder head.TIP:Apply engine oil to the outer surface of newvalve guides.3. Insert the special service tool e into thevalve guide c, and then ream the valveguide.TIP:• Apply engine oil to the inner surface of thevalve guide.• Turn the valve guide reamer clockwise toream the valve guide.• Do not turn the reamer counterclockwisewhen removing it.• Make sure to clean the valve guide afterreaming it.Valve guide inside diameter a:Intake and exhaust:5.504–5.522 mm (0.2167–0.2174 in)Valve stem-to-valve guide clearance= valve guide inside diameter – valvestem diameter:Intake and exhaust:0.025–0.058 mm (0.0010–0.0023 in)Valve guide remover/installer b:90890-06801aabValve guide remover/installer b:90890-06801Valve guide installer d:90890-06810Valve guide reamer e:90890-06804Ecbdce