82
POWERHEAD
CYLINDER HEAD
Valve and Valve Guide
Using a micrometer and a small bore gauge, mea-
sure the diameters on the valve stems and the
guides in order to check the guide to stem clear-
ance. Measure at more than one place along
length of each stem and guide.
Valve stem outside diameter:
•
IN: 0.1565 to 0.1571 in. (3.975 to 3.990 mm)
•
EX: 0.1559 to 0.1565 in. (3.960 to 3.975 mm)
Measure the valve guide inside diameter using a
small bore gauge.
Valve guide inside diameter:
•
IN / EX: 0.1575 to 0.1580 in. (4.000 to 4.012
mm)
Valve guide to valve stem clearance:
•
IN: 0.0004 to 0.0015 in. (0.010 to 0.037 mm)
•
EX: 0.0010 to 0.0020 in. (0.025 to 0.052 mm)
Service limit:
•
IN: 0.0030 in. (0.075 mm)
•
EX: 0.0035 in. (0.090 mm)
If the measurement exceeds the service limit,
replace the valve and/or the cylinder head.
If unable to measure the valve guide inside diam-
eter, measure the valve stem deflection.
Install valves into the valve guide.
Lift valves 8 to 10 mm off seat.
Move the valve head in the direction “X – Y” and
measure the deflection.
Valve stem deflection:
•
IN / EX: 0.014 in. (0.35 mm)
If the measurement exceeds the service limit,
replace the valve and/or the cylinder head.
Valve Stem End
Inspect the valve stem end face for pitting and
wear. If pitting or wear is found, the valve stem
end may be resurfaced. If the chamfer of stem
end has been worn away, replace the valve.
006037
006038
006039
006040
X
y
