Yamaha YZ250X 2022 Owner's Service Manual

CYLINDER HEAD, CYLINDER AND PISTON5-8e. If out of specification, replace the pistonand piston rings as a set.f. Calculate the piston-to-cylinder clearancewith the following formula.g. If out of specification, replace the cylinder,and replace the piston and piston rings asa set.EAM30547COMBINATION OF PISTON AND CYLINDER1. Check:• Cylinder mark “a”2. Check:• Piston mark “a”3. Combination:• Combine the piston and cylinder by the fol-lowing chart.TIPWhen you purchase a cylinder, you cannot des-ignate its size. Choose the piston that matchesthe above chart.Diameter66.352–66.367 mm (2.6123–2.6129 in)a. 17.5 mm (0.69 in) from the bottom edge ofthe pistonPiston-to-cylinder clearance =Cylinder bore - Piston skirt diameterPiston-to-cylinder clearance0.045–0.050 mm (0.0018–0.0020in)Cylinder mark “a” Cylinder sizeA 66.400–66.402 mm(2.61417–2.61425 in)B 66.404–66.406 mm(2.61433–2.61441 in)C 66.408–66.410 mm(2.61449–2.61457 in)D 66.412–66.414 mm(2.61465–2.61472 in)abPiston mark “a”(color) Piston sizeA (red) 66.352–66.355 mm(2.61228–2.61240 in)B (orange) 66.356–66.359 mm(2.61244–2.61256 in)C (green) 66.360–66.363 mm(2.61260–2.61272 in)D (purple) 66.364–66.367 mm(2.61276–2.61287 in)Cylinder mark Piston mark (color)A A (red)B B (orange)C C (green)D D (purple)