It's possible to remove the valve springs from the top without pulling the head. Be sure the piston is at the top of the stroke to keep the valve from falling into the cylinder. This can be done by watching the operation of the valves. Turn the engine clockwise by turning the fan with the spark plugs removed, until the exhaust valve closes, and the intake just begins to open. mark the crank pulley with chalk, and make one full turn. now you're at the top of the compression stroke with both valves closed.
Pry the valve springs down until you can remove the keepers, and remove the springs. Grab the valve stem at the top and wobble it back and forth. There should be little, if any free movement. If there's a noticeable amount of free play, the guides are worn out. Be SURE the piston is at the top, or the valve can fall into the cylinder, and you'll have to remove the head! Reassemble the springs on the valves, and move on to the next cylinder.
Jerry
