1986-1987 Honda TRX350 FourTrax 4X4, 1987-1989 TRX350D Foreman 4X4 Service Manual, Page 92Get this manual
CYLINDERPISTON Install the piston and piston pin, using new piston pin clipsNOTE Face the piston "IN" mark toward the intake valve side Do not align the piston pin clip end gap with the piston cutout Do not let the clip fall into the crankcase
Install new gasket and dowel pins
Coat the cylinder bore and piston rings with engine oil and install the cylinderNOTE Avoid piston ring damage during installationDo not let the cam chain fall into the crankcase