2008 Yamaha Raptor 250SE / 250SE2 Factory Service Manual, Page 147Get this manual
CYLINDER AND PISTON+ ENG
REMOVING THE PISTON 1Remove: Piston pin clips Piston pin Piston NOTE: Before removing the piston pin clip, cover the crankcase opening with clean rag to prevent the piston pin clip from falling into the crankcase Before removing each piston pin, deburr the clip groove and pin hole areaIf the piston pin groove is deburred and the piston pin is still difficult to remove, use the piston pin puller Piston pin puller set 90890-01304 Piston pin puller YU-01304