It is first necessary to mention that the tappets and sleeves are locked in position by the effect of the tapered tappet stem expanding the split adjusting sleeve in the threads .of the rocker. Before the tappet can be adjusted it is necessary to slacken the small lock nut and force the tappet down off its taper seating in the sleeve. If the tappet is tight on its seating the easiest method of removing it is as follows : Insert a screwdriver between the rocker and valve spring collar to give clearance between the tappet and valve stem. By tapping smartly with a small hammer on the top of the tappet stem, it will drop down from its taper seating. The sleeve can now be turned either way by means of the small spanner provided in the tool kit. In making this adjustment, it is necessary to allow for the effect of tightening up the lock nut, which draws in the Tappet, and expands the adjusting sleeve. The clearance for the tappet should be inlet .010", for the exhaust .015". When using machine for racing, increase clearances to ex .020" in .012".

After the Engine has been run, it is as well to again tighten up the Tappet Locking Nuts as these are apt to slacken due to the effect of running the engine which tends to drive the tappet further into the sleeve.