You can do it with the head on. you put some cotton rope in the spark plug hole and just bar the piston up that will hold the valves in place

The other method is to obtain the KD Spark Plug hole adapter. Threaded fitting which screws into the spark plug hole and accepts a threaded adapter for an air hose. Simply put the cylinder at top dead center, fire up the air compressor and use the 100+ pounds of air pressure to hold the valves up, while changing the springs.

The other method is to obtain the KD Spark Plug hole adapter. Threaded fitting which screws into the spark plug hole and accepts a threaded adapter for an air hose. Simply put the cylinder at top dead center, fire up the air compressor and use the 100+ pounds of air pressure to hold the valves up, while changing the springs.

It’s a lot easier if you park the piston at bottom dead center and then pressurize the cylinder. Finding exact top dead center without bolting a timing wheel to the harmonic damper is very difficult.