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3-36 DISASSEMBLY, REASSEMBLY, INSPECTION, AND MAINTENANCE
Valve System
Valve Seat Contact Standard Width and Service Limit (minimum)
– for both Intake and Exhaust
Standart Service Limit
FE120, 170: 0.7 mm (0.028 in) 1.7 mm (0.067 in)
FE250, 290, 350,
400:
0.8 mm (0.031 in) 1.9 mm (0.075 in)
•
Using a 45 (30 only for the intake on FE350 and 400) valve seat
cutter, apply a light force to remove the burrs from the seat.
•
Use a marker (blue ink) on the valve seat to inspect the contact
between the valve and the valve seat. The valve and the seat must
make contact in the center of the contact surface along the entire
circumference as shown in the diagram.
•
If the contact width is inadequate, cut the seat again and lap the
valve.
Rocker Arm and Rocker Shaft
For FE120, 170, 250
•
If abnormal wear is present on the ball surface of the rocker arm,
or the surface that comes in contact with the valve stem and the
pushrod, replace the rocker arm with a new one.
For FE290, 350, 400
•
Using an inside micrometer, measure the bore of the rocker arm
bearing in several places. Because the rocker arm of the FE350
and 400 is made of sheet metal, use a vernier caliper to measure its
bore.
1. Ball surface of rocker arm
Rocker Arm Bearing Bore Service Limit (maximum)
FE290: 12.074 mm (0.4754 in)
FE350, 400: 12.3 mm (0.4843 in)
If the measured value is greater than the service limit, replace the
rocker arm.
•
Using a micrometer, measure the diameter of the rocker shaft in
several places.
A: Rocker Arm
Rocker Shaft Diameter Service Limit (minimum)
FE290, 350, 400: 11.949 mm (0.4704 in)
If the measured value is smaller than the service limit, replace the
rocker shaft
A: Rocker Shaft
Pushrod Inspection
•
Support both ends of the pushrod on V blocks and place a dial gauge
against the center.
•
Gently rotate the pushrod to measure its bend through the fluctuation
of the dial gauge.
Pushrod Bend - for both Intake and Exhaust
FE290, 170: 0.5 mm (0.020 in)
FE250, 290: 0.3 mm (0.012 in)
FE350, 400: 0.5 mm (0.020 in)