The goal was to modify as little as possible on the existing wiring harness, and first try crancking of the motor before connecting the fuel hoses. After getting the startmotor up and running, it was time to mount the fuel tank at the rear, connect the fuel hoses, and start the engine. Crancking and starting succeeded without too many difficulties.
Knowing that the wiring harness was ok and functional, the next step was to find place to put battery, controller, dashboard, ignition key, fuses,.. This required additional mounting features on the frame, and adding some extra length on some parts of the wiring harness.
Due to the repositioning of the radiator, the cooling circuit also had to be completely rerouted.
Link to the video of the motor starting ;