Yamaha YZ250F(V) Owner's Service Manual page 78

Timing chain:
Timing chain type/No. of links
Timing chain adjustment method
Valve, valve seat, valve guide:
Valve clearance (cold)
Valve dimensions:
A
Head diameter
"A" head diameter
"B" face width
"C" seat width
"D" margin thickness
Stem outside diameter
Guide inside diameter
Stem-to-guide clearance
MAINTENANCE SPECIFICATIONS
Item
IN
EX
B
Face width
IN
EX
IN
EX
IN
EX
IN
EX
IN
EX
IN
EX
IN
EX
Standard
92RH2010-114M/114
Automatic
0.10 ~ 0.15 mm
(0.0039 ~ 0.0059 in)
0.17 ~ 0.22 mm
(0.0067 ~ 0.0087 in)
C
Seat width
22.9 ~ 23.1 mm
(0.9016 ~ 0.9094 in)
24.4 ~ 24.6 mm
(0.9606 ~ 0.9685 in)
2.26 mm (0.089 in)
2.26 mm (0.089 in)
0.9 ~ 1.1 mm
(0.0354 ~ 0.0433 in)
0.9 ~ 1.1 mm
(0.0354 ~ 0.0433 in)
0.8 mm (0.0315 in)
0.7 mm (0.0276 in)
3.975 ~ 3.990 mm
(0.1565 ~ 0.1571 in)
4.460 ~ 4.475 mm
(0.1756 ~ 0.1762 in)
4.000 ~ 4.012 mm
(0.1575 ~ 0.1580 in)
4.500 ~ 4.512 mm
(0.1772 ~ 0.1776 in)
0.010 ~ 0.037 mm
(0.0004 ~ 0.0015 in)
0.025 ~ 0.052 mm
(0.0010 ~ 0.0020 in)
2 - 5
SPEC
Limit
----
----
----
----
D
Margin thickness
----
----
----
----
1.6 mm
(0.0630 in)
1.6 mm
(0.0630 in)
----
----
3.945 mm
(0.1553 in)
4.430 mm
(0.1744 in)
4.050 mm
(0.1594 in)
4.550 mm
(0.1791 in)
0.08 mm
(0.003 in)
0.10 mm
(0.004 in)