125
POWERHEAD
SPECIFICATIONS
7
Item
Unit
Data
25 HP
VALVE/VALVE GUIDE
Valve diameter
IN
mm (in)
31.0 (1.22)
EX
mm (in)
26.0 (1.02)
Valve clearance
(when cold)
IN
STD
mm (in)
0.03 – 0.07 (0.001 – 0.003)
EX
STD
mm (in)
0.03 – 0.07 (0.001 – 0.003)
Valve seat angle
IN
30°, 45°, 60°
EX
30°, 45°, 75°
Valve guide to
valve stem
clearance
IN
STD
mm (in)
0.020 – 0.047 (0.0008 – 0.0019)
LIMIT
mm (in)
0.070 (0.0028)
EX
STD
mm (in)
0.035 – 0.062 (0.0014 – 0.0024)
LIMIT
mm (in)
0.090 (0.0035)
Valve guide inside
diameter
IN,EX
STD
mm (in)
5.500 – 5.512 (0.2165 – 0.2170)
Valve stem
outside diameter
IN
STD
mm (in)
5.465 – 5.480 (0.2152 – 0.2157)
EX
STD
mm (in)
5.450 – 5.465 (0.2146 – 0.2152)
Valve guide
protrusion
IN
STD
mm (in)
14.2 (0.5591)
EX
STD
mm (in)
12.5 (0.4921)
Valve stem
deflection
IN
LIMIT
mm (in)
0.014 (0.006)
EX
LIMIT
mm (in)
0.018 (0.007)
Valve stem runout
IN,EX
LIMIT
mm (in)
0.05 (0.002)
Valve head radial
runout
IN,EX
LIMIT
mm (in)
0.08 (0.003)
Valve head
thickness
IN
STD
mm (in)
1.0 (0.0394)
LIMIT
mm (in)
0.5 (0.0197)
EX
STD
mm (in)
1.0 (0.0394)
LIMIT
mm (in)
0.5 (0.0197)
Valve seat width
IN,EX
STD
mm (in)
1.1 – 1.3 (0.04 – 0.05)
Valve spring free length
STD
mm (in)
40.84 (1.608)
LIMIT
mm (in)
39.21 (1.5437)
Valve spring tension
STD
kg (Ib)
11.1 – 12.8 (24.5 – 28.2) at length 31.5 mm (1.24 in)
LIMIT
kg (Ib)
10.2 (22.5) at length 31.5 mm (1.24 in)
