2. Inspection and Adjustment(4) Intake/exhaust valve clearance adjustmentMake measurement and adjustment while the engineis cold.(a) Valve clearance measurement1) Remove the rocker arm cover above cylinderhead.2) Set the No.1 cylinder in the compression TDCTurn the crankshaft to bring the piston of theNo.1 cylinder to its compression top dead centerwhile watching the rocker arm motion, timingscale and the top mark position of the crankshaftpulley.(Position where both the intake and exhaustvalves are closed.)Notes:z The crankshaft shall be turned clockwise as seenfrom the radiator side.z The No.1 cylinder position is on the opposite sideof the radiator and the ignition order shall be1-3-4-2-1 at 180°intervals.z Since the intake and exhaust valve rocker armsare operated the same and there is a clearancebetween the arm and valve generally at the topdead center, the position can be checked bymeans of the play when the arm head is held witha hand. Also see that the crankshaft pulley topmark is positioned at zero on the timing scale. Ifthere is no valve clearance, inspection in thedisassembled state is necessary since the valveseat may be worn abnormally.3) Valve clearance measurementIn case of 2-valve cylinder head insert athickness gage between the rocker arm andvalve cap, and record the measured valveclearance.In case of 4-valve head insert a thickness gagebetween the rocker arm and the valve bridge,and record the measured valve clearance.(Use it as the data for estimating the wear state.)4) Adjusting other cylindersIn case of 4-cylinder engines, turn the crankshaft180 and make adjustment for the No.3 cylinder.Then adjust the No.4 and No.2 cylinders in thisorder.The cylinder to be adjusted first does not have tobe the No.1 cylinder. Select and adjust thecylinder where the piston is the nearest to the topdead center after turning, and make adjustmentfor other cylinders in the order of ignition byturning the crankshaft 180 each time.In case of 3-cylinder engines, turn the crankshaft240 and make adjustment for the No.3 cylinder.Then adjust the No.2 cylinder in this order.40
