Honda CRF450R 2009 Service Manual page 266

CYLINDER HEADNALVES
Adjust the valve guide driver to the valve guide height.
While the cylinder head is still heated, drive new valve
guides Into the cylinder head from the top of the
cylinder (camshaft and rocker arm side).
Check that the valve guides are al the proper depth
using a caliper, adjust the height if necessary.
SPECIFIED DEPTH :
IN : 14.B-15.0 mm (0.58 - 0.59 In)
EX:
17.B- 18.0
mm
(0.70 - 0.71
in)
TOOL :
Valve guide driver
U.S.A. only installation :
07743-0020000
not available In
U.S .A.
Mark the depth of the valve guide using a marker.
Use the valve guide driver to correct the depth.
Lei the cylinder head cool to room temperature.
Use cutting oil on
Ream new valve guides.
the reamer during
Insert the reamer from the combustion chamber side of
this operatlOfl. Take
the cylinder head and always rotate the reamer
care not
to tilt or dockwise .
lean the reamer in
the guide while
reaming.
TOOL:
Val ve guide reamer, 5.0 mm
07984-MA60001
or
07984·MA6000D
(U.S.A. only)
Clean the cylinder head thoroughly to remove any
metal particles after reaming and reface the valve seats
(page
9-24).
VALVE SEAT INSPECTION/REFACING
9-24
Clean the intake and exhaust valves thoroughly to , - - - - -- -- - -
remove carbon deposits.
Apply a light coating of Prussian Blue to the valve seat.
Tap the valves and seats using a rubber hose or other
hand-lapping tool.
Remove the valve and Inspect the valve seat face.
The valve seat contact should be within the specified
width and even aU around the circumference.
STANDARD:
IN : 1.1 - 1.3mm(O.04 - 0.05in)
EX:
1.3 - 1.5
mm
(0.05 - 0.06
In)
SERVICE LIMIT:
IN/EX: 2.0 mm (O.OB In)
- When the service limits are exceeded, replace the
intake valve and recheck the valve seat width.
If the seat width is not within specification, reface the
valve seat (page 9-25).
;t
SEAT WIDTH