Yamaha YXR70FX Service Manual page 41

Item
Timing chain
Model/number of links
Tensioning system
Rocker arm/rocker arm shaft
Rocker arm inside diameter
Shaft outside diameter
Rocker-arm-to-rocker-arm-shaft
clearance
Valve, valve seat, valve guide
Valve clearance–intake (cold)
Valve clearance–exhaust (cold)
Valve dimensions
A
Head Diameter
Valve head diameter "A"
Intake
Exhaust
Valve face width "B"
Intake
Exhaust
Valve seat width "C"
Intake
Exhaust
Valve margin thickness "D"
Intake
Exhaust
Valve stem diameter
Intake
Exhaust
Valve guide inside diameter
Intake
Exhaust
ENGINE SPECIFICATIONS
98XRH2010/126
Automatic
12.000 ~ 12.018 mm (0.4724 ~ 0.4731 in)
11.981 ~ 11.991 mm (0.4717 ~ 0.4721 in)
0.009 ~ 0.037 mm (0.0004 ~ 0.0015 in)
0.09 ~ 0.13 mm (0.0035 ~ 0.0051 in)
0.16 ~ 0.20 mm (0.0063 ~ 0.0079 in)
B
Face Width
37.90 ~ 38.10 mm (1.4921 ~ 1.5000 in)
31.90 ~ 32.10 mm (1.2559 ~ 1.2638 in)
2.26 mm (0.0890 in)
2.26 mm (0.0890 in)
1.00 ~ 1.20 mm (0.0394 ~ 0.0472 in)
1.00 ~ 1.20 mm (0.0394 ~ 0.0472 in)
0.80 ~ 1.20 mm (0.0315 ~ 0.0472 in)
0.80 ~ 1.20 mm (0.0315 ~ 0.0472 in)
5.975 ~ 5.990 mm (0.2352 ~ 0.2358 in)
5.960 ~ 5.975 mm (0.2346 ~ 0.2352 in)
6.000 ~ 6.012 mm (0.2362 ~ 0.2367 in)
6.000 ~ 6.012 mm (0.2362 ~ 0.2367 in)
2 - 6
Standard
C
Seat Width
SPEC
Limit
----
----
----
----
----
----
----
D
Margin Thickness
----
----
----
----
1.60 mm
(0.0630 in)
1.60 mm
(0.0630 in)
----
----
5.945 mm
(0.2341 in)
5.930 mm
(0.2335 in)
6.050 mm
(0.2382 in)
6.050 mm
(0.2382 in)