Honda CRF450R 2009 Service Manual page 284

CYLINDER/PISTON
Measure the piston pin bore 1 .0 .
SERVICE LIMIT: 19.03 mm (0.749 in)
Check the piston pin for wear and excessive
discoloration.
Measure the piston pin 0.0.
SERVICE LIMIT: 18.99
mm
(0.748
in)
'09- '14 If the 0.0. is under the service limit. discolored , or
nearty 30.0 hours of running lime have elapsed, replace
the piston pin.
Affar '14
If the 0.0. is under the service limit, discolored, or
nearly 15.0 hours of running time have elapsed, replace
the piston pin.
Push the ring into
the cyfinder with
the
rop of the PIS/on
1 0
be
sure
the ring
is
squarely in the
cylinder
10·8
Calculate the piston-la-piston pin clearance.
SERVICE LIMIT: 0.04
mm
(0.002
in)
Insert each piston ring into the cylinder and measure
the ring end gap.
SERVICE LIMITS :
Top: 0.32 mm (0.013 in)
Oil (side rail): 0.71 mm (0.028 in)
If the ring end gap under the service limit or near1y 15.0
hour$ of running time have elapsed. replace the piston
ring with a new one.
CONNECTING ROD
Measure the connecting rod small end 1.0.
SERVICE LIMIT: 19.05 mm (0.750 in)
If the
1.0.
is over the service limi!, replace the
crankshaft (page 13-22).
Calculate the connecting rod-to-piston pin clearance.
SERVICE LIMIT: 0.06 mm (0.002 in)