Yamaha TMAX 2020 Service Manual

5-21CYLINDER HEADEAS30276REMOVING THE CYLINDER HEAD1. Remove:• Cylinder head bolt• Cylinder head nutTIP• Loosen the bolts and nuts in the proper se-quence as shown.• Loosen each nut 1/2 of a turn at a time. After allof the nuts are fully loosened, remove them.EAS30277CHECKING THE CYLINDER HEAD1. Eliminate:• Combustion chamber carbon deposit(with a rounded scraper)TIPDo not use a sharp instrument to avoid damag-ing or scratching:• Spark plug bore thread• Valve seat2. Check:• Cylinder headDamage/scratches  Replace.• Cylinder head water jacketMineral deposits/rust  Eliminate.3. Measure:• Cylinder head warpageOut of specification  Resurface the cylinderhead.a. Place a straightedge “1” and a thicknessgauge “2” across the cylinder head.b. Measure the warpage.c. If the limit is exceeded, resurface the cylin-der head as follows.d. Place a 400–600 grit wet sandpaper on thesurface plate and resurface the cylinderhead using a figure-eight sanding pattern.TIPTo ensure an even surface, rotate the cylinderhead several times.EAS30282INSTALLING THE CYLINDER HEAD1. Install:• Dowel pin• Cylinder head gasket2. Install:• Cylinder head• Washer• Cylinder head nut• Cylinder head boltTIP• Pass the timing chain through the timing chaincavity.• Lubricate the cylinder head nuts and washerswith engine oil.3. Tighten:• Cylinder head nut “1”–“6”• Cylinder head bolt “7”, “8”• Cylinder bolt “9”Warpage limit0.10 mm (0.0039 in)4223754861 2G088954Thickness gauge90890-03268Feeler gauge setYU-26900-921G088957NewNewNew