Yamaha YTZ250S 1986 Service Manual page 40

II
ENGINE MAINTENANCE AND
REPAIR
PREPARATION FOR SERViCE ........................................ 3-1
CARBURETOR ........................................................ 3-2
Tuning ............................................................. 3-3
Tuning and Repair Parts ............................................ 3-7
Main Jet Replacement .............................................. 3-7
Removal ........................................................... 3-8
Inspection .......................................................... 3-8
Float Height ........................................................ 3-8
REED VALVE ......................................................... 3-9
Inspection .......................................................... 3-9
EXHAUST PIPE AND MUFFLER ..................................... 3-10
Removal .......................................................... 3-10
Maintenance ...................................................... 3-10
CYLINDER HEAD .................................................... 3-11
Removal .......................................................... 3-11
Maintenance ...................................................... 3-12
CYLINDER ........................................................... 3-13
Removal .......................................................... 3-13
Maintenance ...................................................... 3-13
PISTON ............................................................. 3-14
Removal .......................................................... 3-14
Maintenance .......... . . ........................................... 3-14
Piston Clearance .................................................. 3-15
Piston Rings ...................................................... 3-15
Piston Pin, Bearing ................................................ 3-16
Assembly ......................................................... 3-16
CRANKCASE COVER ................................................ 3-17
Removal .......................................................... 3-17
Assembly ......................................................... 3-17
WATER PUMP ...................................................... 3-18
Disassembly ....................................................... 3-18
Inspection ......................................................... 3-18
Assembly ......................................................... 3-18