Cylinder Headnalves - Honda CRF450R 2009 Service Manual

CYLINDER COMPRESSION TEST
Warm up the engine .
SlOp the engine, and remove the spar!( plug
(page 4·11
I.
Install a compression gauge attachment into the spa rk
plug hole.
TOOL:
Compression gauge 07RMJ·MY50100 or
attachment 07AMJ-MENA200 (U.S.A. only)
or equivalent commercially available in U.S.A .
Connect a compression gauge onlo the compression
gauge attachment.
Temporarily install the fuel lank.
Open the throttle fu lly.
Operate the kickslarter pedal forcefully several times
until the gauge needle stops moving.
COMPRESSION :
'09· ' 12: 392 kPa (4.0 kg/em' , 57 psi) at 600 rpm
After '12: 647 kPa (6.6 kg/em', 94 psi) at 600 rpm
Low compression can be caused by :
- Improper valve adjustment
- Valve leakage
- Blown cylinder head gasket
- Worn piston rings or cylinder (page 10-6)
High compression can be caused by :
- Carbon deposits on piston head or combustion
chamber
- Faulty decompressor system
CYLINDER HEAD COVER
REMOVAL
Hang the fuel tank to the left side of the frame
(page 4-6).
Disconnect the spark plug cap and crankcase breather
hose.
Remove the bolts, rubber seals and cylinder head
cover.
CYLINDER HEADNALVES
I
COMPRESSION GAUGE
9-7