Easiest ever 2 stroke engine compressed air conversion, This took me 30 mins to set up from scratch, Running a 2 stroke 30cc MTD strimmer petrol engine on compressed air, With just a cam molded onto the flywheel out of "Ceys Super Bar" to open a trigger operated stander air gun at tdc and keep it open until the exhaust port is open. The trigger air gun is connected by a standard rubber air hose to a 1/4" standard air connector which is screwed into the spark plug hole using a rubber washer and the trigger is screwed to a steel plate, the plate is then screwed to the crankcase. The trigger gun then closes after the cam passes it and then air leaves through the exhaust port, the piston comes back up to the top and the cycle starts again. Why others have difficulty with this and use all sorts of complex valves i dont know!