Managed to clean up the cylinder head a bit, so that it was ready to be re-installed.
A few pictures to show how to set the correct cam timing.
The “T” mark on the stator rotor should be positioned at twelve o’clock, in order to be sure that piston is at the top center.
The “O” on the sprocket should be in line with the little notch in the front of the timing sprocket opening, at nine o’clock.