Honda CRF450R Owner's Manual page 87

Piston/Piston Rings/Piston Pin
Piston/Piston Pin/Piston Ring Inspection
We recommend you consult an official Honda
Service Manual or your dealer for correct Service
Limit measurements.
80
Servicing Your Honda
Piston Ring Installation
1. Remove the carbon deposits from the piston
head and piston ring grooves.
NOTICE
Do not damage the piston when removing the
carbon deposit.
2. Apply engine oil to each piston ring whole
surface.
3. Install the spacer (1) first, then install the side
rails (2) to the piston (3).
4. Install the top ring (4) to the piston with "R"
mark (5) side facing up.
NOTICE
Do not damage the piston ring by spreading the
ends too far.
Do not damage the piston during piston ring
installation.
5. After installing the piston rings they should
rotate freely, without sticking.
Space the ring end gaps 180 degrees apart
between top ring and upper side rail.
Space the ring end gaps 90 degrees apart
between upper side rail, spacer and lower side
rail.
(5)
(4)
(2)
(1)
(2)
(3)
(1) spacer (4) top ring
(2) side rails (5) "R" mark
(3) piston
(4)
(2)
(1)
(2)