Hi Martin, you have the correct magneto, to set the timing loosen the lower of the two timing chain sprockets ( the smallest one ) set the crank to exactly top dead center. With the timing chain lower sprocket slack, rotate the larger sprocket on the magneto until you hear it click, reverse rotate the mag sprocket about 60 degrees and nip up the lower sprocket clamping bolt. Make a mark on the flywheel and the crankcase at top dead centre. Turn the crank over until you hear the magneto click and observe the position of your two timing marks, if they match job done, if not note how much they are apart either advanced or retarded and then slacken lower sprocket clam and loosen sprocket on the taper move the magneto sprocket in whichever direction needed to close the gap on your marker points, clamp up the sprocket and repeat turnover repeat until the click and your two TDC timing marks are all lined up. This will create spark ignition for starting at top dead centre. Make sure that the magneto internals move freely so that when the engine starts it can advance to 20 degrees and return to Zero when the engine stops.. Have Fun!
