Something MAJOR wrong here ! The spigot on the top of the cylinder head is the OUTLET for the hot coolant, rising by ‘thermo-syphon’ effect. That should connect to the top connection on the radiator, where it gets cooled and thus sinks to the bottom of the radiator, from where it should go to the lower (front) connection on the cylinder barrel….. The radiator hose connection spigot would therefore appear to be back-to-front !
Brian
