Honda CRF450X 2007 Owner's Manual page 72

2. Rotate the crankshaft by turning the primary
drive gear bolt (2) clockwise until the "punch"
mark (3) on the primary drive gear aligns with
the index mark (4) on the right crankcase
cover. In this position, the piston may either
be on the compression or exhaust stroke.
If the crankshaft passed the "punch" mark,
rotate the primary drive gear bolt clockwise
again and align the "punch" mark with the
index mark.
The inspection must be made when the piston
is at the top of the compression stroke when
both the intake and exhaust valves are closed.
This condition can be determined by moving
the exhaust rocker arm (5). If it is free, it is an
indication that the valves are closed and that
the piston is on the compression stroke. If it is
tight and the valves are open, rotate the
primary drive gear bolt 360° and realign the
"punch" mark to the index mark.
(2)
(3)
(2) primary drive gear bolt (4) index mark
(3) "punch" mark
(5)
(5) exhaust rocker arm
Valve Clearance And Decompressor Arm
Clearance Inspection
1. Measure the intake valve clearance by
inserting a feeler gauge (1) between the valve
lifters (2) and intake cam lobes (3).
(4)
(1)
(2)
(1) feeler gauge
(2) valve lifters
(3) intake cam lobes
Valve Clearance:
IN: 0.006 ± 0.001 in (0.16 ± 0.03 mm)
Valve Clearance
2. Measure the exhaust valve clearance by
inserting a feeler gauge (1) between the
exhaust rocker arm (4) and shims (5).
(1)
(4)
(1) feeler gauge
(4) exhaust rocker arm
(5) exhaust valve shims
Valve Clearance:
EX: 0.011 ± 0.001 in (0.28 ± 0.03 mm)
If intake valve clearance and exhaust valve
clearance need adjustment, see Camshaft Holder
Assembly Removal (page 68) and select the
correct shim for each valve.
(3)
(5)
(cont'd)
67
Servicing Your Honda