1986-1989 Honda TRX250 FourTrax 250R Service Manual, Page 67Get this manual
CYLINDER HEADCYLINDERPISTON IN ST ALLATION Install the exhaust chamber joint pipe, reed valve and intake pipe(1) REED VALVE
{2} JOINT PIPE
Lubricate the piston rings and piston ring grooves with clean 2-stroke oilInstall the piston rings on the pistonNOTE Install the piston rings with the marks facing upAvoid piston and piston ring damage during installation Do not interchange the top and second rings
(4) PISTON RING
MARKING
Lubricate the small end bearing and piston pin with clean 2stroke oilInstall the connecting rod small end bearingpiston and piston pin NOTE Install the piston with the "IN" mark facing the intake side