Honda CRF450R 2017 Owner's Manual & Competition Handbook page 82

Piston/Piston Pin/Piston Ring Inspection
We recommend you consult an official Honda
Service Manual or your dealer for correct Service
Limit measurements.
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 "1R"
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.
Piston/Piston Rings/Piston Pin
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)
(1) spacer (4) top ring
(2) side rails (5) "1R" mark
(3) piston
Servicing Your Honda
(4)
(2)
(1)
(2)
(4)
(2)
(1)
(2)
(3)
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