There are likely to be air leaks around manifold-cylinder head joints, unless manifold is perfectly aligned with cylinder head intake port face, rubber "O" rings are in good condition and manifold clamps securely tightened. Air leakage will affect carbure-tion, particularly at low speeds.

If all necessary steps have been taken and air continues to leak around manifold-cylinder head joints, it may be necessary to loosen the cylinder base nuts to allow final shifting and alignment of cylinders and manifold. Be sure to tighten base nuts after alignment.

Check tappet adjustment as described below and reassemble remaining parts.


To get the maximum power and best all-around performance from an engine, keep valve tappets properly adjusted. They should be inspected and, if necessary, readjusted initially at 500 and 1000 miles and every 2000 miles thereafter.

Engine must be cold during tappet adjustment. As each tappet is readjusted, make sure it is at its lowest position, by turning engine ahead until the like tappet in the other cylinder is at its highest position (valve fully opened). The inlet valves are those nearest the carburetor.

To uncover tappets, press down on push rod cover spring retainer, and remove keeper at upper end. Cover then telescopes. Loosen tappet adjusting screw lock nut (3) and turn adjusting screw (2) downward (into tappet body) until push rod is just free and has noticeable shake. When checking for push rod shake, grasp push rod with finger tips just below cylinder head, and shake toward front and rear of engine. Slowly turn adjusting screw upward (toward push rod) until nearly all play is removed. At this point, lock tappet screw lock nut against tappet body (4) and recheck for correct tappet adjustment. A tappet is correctly readjusted when push rod has slight amount of play or shake, and can be turned freely with finger tips, completely around, without trace of bind.

When reassembling push rod covers, make sure that both ends of covers are properly seated against cork washers.

1. Push rod

2. Tappet adjusting screw

3. Tappet adjusting screw lock nut

4. Tappet body


Before attempting to remove push rod and cover assembly, turn engine until tappet is at its lowest position. Turn adjusting screw lock nut (3) all the way up to end of thread on adjusting screw (2). Turn adjusting screw (2) all the way down into tappet body. Remove push rod and cover assembly by prying push rod upward and to one side, be careful not to bind push rod upper end in aluminum rocker arm housing.

Doing so may result in a bent push rod. Install new cork washers (3, Fig. 3B-6) in aluminum rocker arm housing and in tappet guide, being careful not to damage them and making sure they are well seated. Replace cork washer (3, Fig. 3B-6) in push rod cover with a new one.

Reassemble push rod and push rod cover assembly in reverse order of disassembly. Check tappet adjustment as described in "Adjusting Tappets."

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