4 - 20
ENG
INSPECTION AND REPAIR
INSPECTION AND REPAIR
CYLINDER HEAD
1.Eliminate:
●
Carbon deposit
Use a rounded scraper
1
.
NOTE:
Do not use a sharp instrument to avoid
damaging or scratching:
●
Spark plug threads
●
Valve seat
●
Cylinder head
2.Measure:
●
Cylinder head warpage
Out of specification
→
Resurface/Replace.
Cylinder head warp:
Less than 0.10 mm (0.004 in)
INTAKE AND EXHAUST VALVE
1.Check:
●
Valve face
●
Stem end
Wear/Pitting/Out of specification
→
Replace.
Minimum thickness (service limit)
a
:
0.8 mm (0.031 in)
Beveled
b
:
0.5 mm (0.020 in)
Minimum length (service limit)
c
:
4.0 mm (0.157 in)
2.Inspect:
●
Valve stem end
1
Mushroom shape/Larger diameter than
rest of stem
→
Replace valve, valve guide,
and oil seal.
NOTE:
Deburr any deformed valve stem end
1
.
Use an oil stone to smooth the stem end.
4
Summary of Contents for BEARTRACKER YFM250XC
Page 1: ...SERVICEMANUAL LIT 11616 12 01 4XE F8197 10 YFM250XL C ...
Page 24: ...GEN INFO 1 10 1 ...
Page 54: ...2 30 SPEC 2 ...
Page 98: ...INSP ADJ 3 44 3 ...
Page 176: ...ENG 4 78 4 ...
Page 186: ...CARB 5 10 5 ...
Page 228: ...6 42 DRIV 6 ...
Page 273: ...8 3 ELEC SWITCH INSPECTION 8 ...
Page 312: ...PRINTED IN U S A YAMAHA MOTOR CO LTD 2500 SHINGAI IWATA SHIZUOKA JAPAN ...
Page 313: ...SUPPLEMENTARY SERVICEMANUAL LIT 11616 14 17 4XE F8197 11 YFM250XN ...
Page 372: ...PRINTED IN U S A YAMAHA MOTOR CO LTD 2500 SHINGAI IWATA SHIZUOKA JAPAN ...
Page 374: ...YFM250XP SUPPLEMENTARY SERVICEMANUAL LIT 11616 15 03 4XE F8197 12 ...
Page 397: ...YAMAHA MOTOR CO LTD 2500 SHINGAI IWATA SHIZUOKA JAPAN PRINTED IN U S A ...