Yamaha YZ450F(Y Owner's Manual page 26

Timing chain:
Timing chain type/No. of links
Timing chain adjustment method
Valve, valve seat, valve guide:
Valve clearance (cold)
IN
EX
Valve dimensions:
"A" head diameter (IN)
"A" head diameter (EX)
"B" face width (IN)
"B" face width (EX)
"C" seat width (IN)
"C" seat width (EX)
"D" margin thickness (IN)
"D" margin thickness (EX)
Stem outside diameter (IN)
Stem outside diameter (EX)
Guide inside diameter (IN)
Guide inside diameter (EX)
Item
MAINTENANCE SPECIFICATIONS
Standard
98XRH2010-118M/118
Automatic
0.10–0.15 mm (0.0039–0.0059 in)
0.20–0.25 mm (0.0079–0.0098 in)
26.9–27.1 mm (1.0591–1.0669 in)
27.9–28.1 mm (1.0984–1.1063 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)
1 mm (0.0394 in)
1 mm (0.0394 in)
4.475–4.490 mm (0.1762–0.1768 in)
4.965–4.980 mm (0.1955–0.1961 in)
4.500–4.512 mm (0.1772–0.1776 in)
5.000–5.012 mm (0.1969–0.1973 in)
2-4
Limit
----
----
----
----
----
----
----
----
1.6 mm (0.0630
in)
1.6 mm (0.0630
in)
0.85 mm (0.033
in)
0.85 mm (0.033
in)
4.445 mm
(0.1750 in)
4.935 mm
(0.1943 in)
4.550 mm
(0.1791 in)
5.050 mm
(0.1988 in)