INLET AND EXHAUST VALVES.


When the gas is at the highest point of compression, the spark occurs, an explosion takes place and the piston is forced out on the work stroke. It is then necessary to get rid of the burnt gas so that a new mixture can be drawn into the cylinder for the next explosion.

At the end of the work stroke, the cam on the cam gear pushes the cam rod toward the cylinder head. This works the lever on the head of the engine and opens the exhaust valve "B" so the burnt gas is forced out through the muffler.

LEAKI NG VALVES.

If the engine does not furnish its full power, you may find it is due to loss of compression, which can be determined by a hissing sound at the piston end of the cylinder, at the igniter or at the cylinder head. if it occurs at the valves, there is either an obstruction on the valve, preventing it from closing, or it is worn on one side more than the other. In case the valves are worn or they are covered with a carbon deposit, you will have to regrind the valves to prevent their leaking.

HOW TO GRIND THE VALVES.

When an inlet or exhaust valve leaks, remove the cylinder head, take off the valve springs, remove the valve you want to grind and wash it and the valve seat in gasoline, then make a paste of fine emery dust and oil. If you cannot get emery dust, use pumice stone with oil (you can get pumice stone at most any drug store). Smear this on the valve and valve seat, put the valve in place and put a nail through the hole in valve stem on the outside of the head, grasp the nail with your fingers and turn from left to right for a minute or so, then lift the valve and turn it about half way around and repeat this until the valve and valve seat show an even surface all the way around.

After the valve is ground in, wash off the emery dust with gasoline and do not get any dirt on the valve seat. In replacing the valves be sure to get the heavy spring on the exhaust valve and the light spring on the inlet valve.

- 26-