kennyk

hi all, am new here and wondering if anybody knows how to time the valves on a kelvin 3 hp petrol paraffin single poppet valve. it was running fine until the mag sprocket came loose and dropped off stripping some teeth of the fiber cam drive cog I put another sprocket off a two cylinder engine on, it's the exact same but no timing marks on it,,got the engine to run (trial and error) but rough,blowing out oil and fuel, and stops after a minute or two,,doing my head in,,any advise would be welcome apart from using it as an anchor,,,YET,,,,,cheers,,kenny