Cylinder Head/Valves Inspection; Valve Seat Width - Honda GX240RT2 Service And Repair Manual

CYLINDER HEAD/VALVES
INSPECTION
CYLINDER COMPRESSION CHECK
Start the engine and warm up to normal operating
temperature.
Turn the fuel valve lever to the OFF position, and then
loosen the drain screw to drain the carburetor.
Remove the spark plug cap (1) from the spark plug.
Remove the spark plug using a spark plug wrench.
Pull the recoil starter several times to expel unburned
gas.
Attach a commercially available compression gauge set
EEPV303A (2) to the spark plug hole.
Pull the recoil starter forcefully to measure stable
cylinder compression.
CYLINDER COMPRESSION:
0.51 - 0.69 MPa (5.2 - 7.0 kgf/cm
600 min
CYLINDER HEAD WARPAGE
Remove the carbon deposits from the combustion
chamber
Check the spark plug hole and valve areas for cracks.
Check the cylinder head warpage using a straightedge
(1) and thickness gauge (2).
SERVICE LIMIT:
If the measurement is more than the service limit,
replace the cylinder head

VALVE SEAT WIDTH

Remove the carbon deposits from the combustion
chamber(page
Inspect each valve for face irregularities.
If necessary, replace the valve
Apply a light coat of Prussian Blue or erasable
felt-tipped marker ink to each valve seat.
Insert the valve, and snap it closed against its seat
several times. Be sure the valve does not rotate on the
seat. The transferred marking compound will show any
area of the valve face that is not concentric.
Measure the valve seat width of the cylinder head.
STANDARD:
SERVICE LIMIT:
If the measurement is more than the service limit,
recondition the valve seat
Check whether the valve seat contact area of the valve
is too high or too low.
If the valve seat is too high or too low, recondition the
valve seat
gx240ut2_gx270ut2_gx340ut2_gx390ut2
2
, 74 - 100 psi) /
-1
(rpm)
(page 3-13).
0.10 mm (0.004 in)
(page 12-3).
3-13).
(page
1.0 – 1.2 mm (0.04 – 0.05 in)
2.0 mm (0.08 in)
(page 12-10).
(page 12-10).
(2)
(1)
12-4).
VALVE SEAT
WIDTH
CYLINDER HEAD/VALVES
(2)
(1)
VALVE LAPPER
LIL21100
(Commercially
available)
CONTACT TOO HIGH