kelvin engin

Hi all hoping that someone will know how to time the valves on a kelvin 3hp single poppet valve, was going fine until the mag sprocket fell off and stripped four of teeth on the fiber cam drive thats driven by a cog on the flywheel, i put another drive on but theirs no timing marks on it,got it running (trial and error, flywheel on and off at least a thousand times) but not right its blowing oil out, and fuel out the carb and just runs for a minuet or two ,,,,I have a vague memory about something to do with degrees and valve timing,,,but hoping that someone will know how it's done,,,,,kenny