Maintenance Manual and Instruction Book, 16H, Big 4, 18 and ES2

.Set clearances with engine cold. When timing engine with these cams there should be a .017" feeler inserted between cam and crankcase rocker pad. Adjust afterwards to correct clearance. 21. TO ADJUST TAPPETS OR PUSH RODS. Release the middle hexagon—locking the nut—by placing one spanner on the bottom hexagon—the tappet stem or push rod—and the second on the locking nut. (Fig. 6-7.) Turn the top hexagon—the tappet head or push rod adjuster—in the desired direction, and when the correct clearance is obtained, tighten locking nut. Check clearance after tightening locking nut.

To remove exhaust valve lifter, remove cable from lifter arm. Remove securing pin in top of rocker box and withdraw the lifter complete with arm. The rocker ball ends and valve rocker pads are pressed into the rocker arms and may be knocked out for replacement.

20. TAPPET OR PUSH ROD ADJUST­ MENT ON MACHINES WHERE ENGINE NO. IS FOLLOWED BY THE LETTER Q. Engines having a number followed by the above suffix are fitted with a modified cam form which requires rather more careful positioning of the cam than previously. For both O.H.V. and S.V. engines pro­ ceed as follows:— To adjust inlet valve clearance rotate engine till exhaust valve is just lifting. Adjust inlet tappet or push rod (para. 21). To adjust exhaust valve clearance rotate engine till inlet valve has just closed. Adjust exhaust tappet or push rod. On S.V. engines there should be .010" clearance between tappet head and valve on inlet and exhaust. On O.H.V. engines both push rods should be free to rotate without any up and down movement.

Fig. 7. O.H.V. PUSH ROD ADJUSTMENT.

SEAUNfi WAfl>4ra

L o c k o u t

Fig. 6. S.V. TAPPET ADJUSTMENT 12