2006-2012 Honda TRX90 TRX90EX/X Service Manual, Page 126Get this manual
CYLINDERPISTON PISTON INSTALLATION When cleaning the cylinder mating surface, place shop towel over the cylinder opening to prevent dust or dirt from the entermg engine
Clean off any gasket materials from the crankcase surfaceApply engine oil to the connecting rod small end hole
Apply engine oil to the piston, piston pin outer surfaceInstall the piston with its "INmark facing the intake sideDo not align the piston pin clips end gap With tile piston cut-outDo not let the piston pm clips fall into the crankcase