Honda FQ650, Manual

Page: 86 / 130

CYLINDER HEAD
12-5
CYLINDER HEAD/VALVES
INSPECTION
CYLINDER COMPRESSION CHECK
Start the engine and warm up to normal operating
temperature.
Turn the engine stop switch to the OFF position.
Turn the fuel valve lever to the OFF position, and then
loosen the drain screw of the carburetor to drain the fuel
completely (page 5-3).
Remove the spark plug (page 3-12).
Pull the recoil starter several times to expel unburned
gas.
Attach a commercially available compression gauge [1]
to the spark plug hole.
Pull the recoil starter forcefully to measure stable
cylinder compression.
CYLINDER HEAD WARPAGE
Check the spark plug hole and valve areas for cracks.
Clean any gasket material from the cylinder head
mating surface and check the cylinder head warpage
using a straightedge [1] and feeler gauge [2].
• Be careful not the damage the mating surface.
If the measurement is more than the service limit,
replace the cylinder head.
CYLINDER COMPRESSION:
0.35 MPa (3.6 kgf/cm 2 , 51 psi)/600 min -1 (rpm)
[1]
SERVICE LIMIT: 0.10 mm (0.004 in)
[2] [1]