Yamaha YZ250R Service Manual

Contents

4-29CYLINDER HEAD, CYLINDER AND PISTON ENG7. Install:9O-ring 19Side holder 29Screw (side holder) 39YPVS breather hose 4NOTE:9Apply the lithium soap base grease on the O-rings.9Install the side holder with its projection afacing upward.8. Install:9Gasket (power valve cover) 19Power valve cover 29Screw (power valve cover) 3NOTE:9Install the gasket with its cut a facing down-ward and the seal print side toward the powervalve cover.9Install the power valve cover so that the arrowmark b faces upward.EC475233Piston ring and piston1. Install:9Piston ring 1NOTE:9Take care not to scratch the piston or damagethe piston ring.9Align the piston ring gap with the pin 2.9After installing the piston ring, check thesmooth movement of it.2. Install:9Gasket (cylinder) 19Small end bearing 29Dowel pin 3NOTE:9Apply the engine oil onto the bearing (crank-shaft and connecting rod) and connecting rodbig end washers.9Install the gasket with the seal print side towardthe crankcase.4 Nm (0.4 m•kg, 2.9 ft•lb)4 Nm (0.4 m•kg, 2.9 ft•lb)