Honda CRF450RX 2020 Owner's Manual & Competition Handbook page 95

Piston/Piston Rings/Piston Pin
Cylinder Removal
1. Remove the cylinder (1) while holding the
piston (2).
Do not let the cam chain fall into the crankcase.
Do not pry on or strike the cylinder.
(1) cylinder (2) piston
2. Remove the dowel pins (3) and cylinder gasket
(4).
Do not let the cam chain fall into the crankcase.
Do not let the dowel pins fall into the crankcase.
(3)
(3) dowel pins (4) cylinder gasket
90
Servicing Your Honda
Piston Removal
1. Place clean shop towels (1) in the crankcase to
keep the piston pin clips, or other parts, from
falling into the crankcase.
2. Remove the piston pin clips (2) using a pair of
needle-nose pliers.
3. Press the piston pin (3) out of the piston (4),
and remove the piston.
(CRF450RX)
(1)
Under racing conditions, the piston, rings and
piston pin should be replaced every 4 races or
about every 15.0 hours of running.
(CRF450R/RWE)
Under racing conditions, the piston, rings and
piston pin should be replaced every 6 races or
about every 15.0 hours of running.
(2)
Be careful not to damage or shock the piston pin.
Do not clean the piston pin using a commercially
available compound cleaner.
(4)
(4)
(3)
(1) shop towels
(2) piston pin clips
Piston Ring Removal
Spread each piston ring (1) and remove by lifting it
up at a point just opposite the gap.
Do not damage the piston ring by spreading the
ends too far.
(1) piston ring
(2)
(1)
(3) piston pin
(4) piston
(1)