Cylinder Compression; Cylinder Head Cover Removal/ Disassembly - Honda TRX680FA Service Manual

CYLINDER HEAD/VALVE/CAMSHAFT
CYLINDER COMPRESSION
Warm up the engine to normal operating tempera-
ture.
Stop the engine, disconnect the spark plug cap and
remove the spark plug (page 4-7).
Install the compression gauge into the spark plug
hole.
TOOLS:
Compression tester
Adaptor
EEPV303A
MT26J200
Shift the transmission in neutral.
Open the throttle all the way and crank the engine
with the starter motor until the gauge reading stops
rising. The maximum reading is usually reached
within 4 - 7 seconds.
COMPRESSION PRESSURE:
510 kPa (5.2 kgf/cm
2
, 74 psi) at 390 rpm (min
1
)
Check that there is no leakage at the gauge connec-
tion.
Low compression can be caused by:
- blown cylinder head gasket
- improper valve adjustment
- valve leakage
- worn piston ring or cylinder
High compression can be caused by:
- carbon deposits in combustion chamber or on
piston head
COMPRESSION GAUGE
CYLINDER HEAD COVER REMOVAL/
DISASSEMBLY
REMOVAL
Remove the fuel tank and heat guard plate (page 6-
39).
Remove the following and set the piston position to
Top Dead Center on the compression stroke (page
4-8):
- timing hole cap
- four bolts and valve adjusting hole caps
VALVE ADJUSTING HOLE CAPS
9-6