Cylinder Compression Test; Cylinder Head Cover Removal - Honda CRF450X 2005 Service Manual

I
\
CYLINDER COMPRESSION TEST
To avoid discllarging
the barrery. do not
operate the starter
motor for more
than 7 seconds.
Warm up the engine .
Stop the engine and remove the spark plug (page 4-
12).
Connect a compression ga uge.
Open the th rottle fully.
Crank the engine with the electric starter or
kickstarter until the gauge needle stops moving.
The maximum reading is usually reached within 4-7
seconds when using electric sta rt er.
COMPRESSION : 402 kPa (4.1 kg /cm2, 58 psi)
at 360 rpm
low compression can be caused by:
- Improper valve adjustment
- Valve leakage
- Blown cylinder head gasket
Worn piston ring or cylinder
- Faulty decompressor system
High compression can be caused by:
- Carbon deposits in combustion chamber or on
piston head
- Faulty decompressor system
CYLINDER HEAD COVER REMOVAL
Remove the fuel tank (page 3-8) .
Disconnect the spark plug cap and crankcase
breather hose.
Remove the bolts, cylinder head cover and packi n g.
CYLINDER HEADIVALVES
COMPRESSION GAUGE
9-7