1981-1984 Official Honda ATC250R Shop Manual, Page 55Get this manual
ATe 250R PISTONCYLINDER INSTALLATION
NOTE Install the piston rings with the manufacturer's marks facing upDo not interchange the top and bottom rings
CYLINDER HEADCYLINDERPISTON
PISTON RING MARK Lubricate the small end bearing and piston pin with clean 2-stroke oilI nstall the connecting rod small end bearing, piston and piston pinNOTE Install the piston with the "IN" mark facing the intake sideInstall the piston pin clipNOTE Use new pin clipsNever re-use old clips Do not let the clips fall into the crankcase