An easy way to test your engine without stripping anything down.
THIS IS THE HARD PART,
Old Spark plug cut off the porsalin, drill out and solder a valve from a heavy duty tyre.

NOW WE CAN BEGIN

Take off Air filter.
Take off rad cap.
Take out OIL DIP STICK.
Take off Rocker Cover
Make sure No1 Valve is CLOSED (Inlet )

Chock ALL wheels as well as the hand brake. (Emergency).
Take out all plugs.
Turn engine over, BY HAND till piston is half way up bore.
Place the valved plug in No1 cylinder,then put in compressed air to about 15psi.
DO NOT PUT TOO MUCH PRESSURE INTO BORE, OR YOU MIGHT RUN YOURSELF OVER.

Place flame at Carb Mouth=== If flame blows out (Inlet is Leaking )

Close Exhaust Valve ==== If flame blows out at the Rear Tailpipe (Muffler) (The Exhaust Valve is leaking)

If Rad bubbles then ====== Head Gasket is leaking.

If air comes up Dipstick, =====If flame blows out (It is bypassing the Rings.)

Just do them ALL in turn and it will tell you the condition of your engine.

So you see this can all be achieved with ONE OLD SPARK PLUG and a little "hot" AIR.

Regards PC 49