well i have not done one but it should be pretty easy,the camshaft will have 2 lobes on it one for the inlet and one for the exhaust turn the engine over until the T mark on the magneto it lined up with a mark on the crankcase if you cant find this then make your own by taking the spark plug out putting a thin screwdriver in the plug hole and turning the engine over by hand until the screwdriver is at its highest point (furthest out of the hole)this will be tdc top dead centre ,mark the magneto and the crankcase in the same position.then look at the cam lobes and see that they are either facing up and out/in or down and out or in you want them to be facing down away from the followers they will diagonally facing away from each other there is usually a flat line on the cam sprocket that goes level with the head or a dot mark that lines up with the centre of the cam caps.
adam bike doctor(of milton keynes motorcycle centre), October 2010
