Cylinder Compression; Cylinder Head Cover Removal; Camshaft Holder Removal - Honda TRX450R Service Manual

CYLINDER HEAD/VALVE
CYLINDER COMPRESSION
Warm the engine to normal operating temperature.
Stop the engine and remove the spark plug (page 4-
9).
Install the compression gauge into the spark plug
hole.
Shift the transmission in neutral.
Open the throttle all the way and operate the
kickstarter forcefully several times until the gauge
reading stops rising.
The cylinder COMPRESSION PRESSURE:
compression
specification is
comparatively low
because the
camshaft has a
decompression
device installed.
'04 - '05:
745 kPa (7.6 kgf/cm
2
,108 psi)
After '05:
TRX450ER;
343 - 382 kPa (3.5 - 3.9 kgf/cm
2
, 50 - 56 psi)
TRX450R;
961 - 1000 kPa (9.8 - 10.2 kgf/cm
2
,139 - 145 psi)
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
Remove the following:
- fuel tank (page 3-9)
- heat guard plate
('04 - '05: page 3-9, After '05: page 3-9)
- spark plug cap (page 4-9)
- crankcase breather hose
- three bolts and special washers
- cylinder head cover
HEAD COVER
CAMSHAFT HOLDER REMOVAL
Remove the following:
- cylinder head cover (page 11-8)
- spark plug (page 4-9)
Remove the crankshaft hole cap and set the piston
position to Top Dead Center on the compression
stroke (page 4-10).
CRANKSHAFT HOLE CAP
11-8