2000-2003 Honda TRX350 Rancher factory service manual, Page 130Get this manual
CYLINDERPISTON PISTON INSTALLATION Place clean shop towel over the crankcase to prevent the clip from falling into the crankcaseApply molybdenum oil solution to the piston pin outer surfaceApply engine oil to the piston pin hole and connecting rod inner surfaceInstall the piston with the IN'' mark toward the intake side and insert the piston pin through the piston and connecting rodPISTON PIN Install new piston pin clips into the grooves in the piston pin holePISTON IN'' MARK
Make sure that the piston pin clips are seated securelyDo not align the piston pin clip end gap with the piston cutout