The negative cable, which is normally connected to the negative pole of the battery, is fastened to the crankcase. From here, the cable branches off and splits up within the electrical system to carry the ground connection to the different elements in the system.

The image shows the ground connection on left side of the engine crankcase.
The battery charging circuit and power distribution
Electrical power for lighting and signalling devicesReassembly of the control unit
Insert the control unit (4) into the protecting sheath (5) and position it on
the airbox.
Position the relay supporting bracket (2) by starting and tightening the
screws (1) to a torque of 6 nm +/- 10% (sect. 3 -
3, Frame torque settings), and connect the control unit connectors (3).
...
Braking
Slow down in time, shift down to engine-brake first and then
brake applying both brakes. Pull the clutch lever before
stopping the motorcycle, to avoid sudden engine stop.
Abs system
Using the brakes correctly under adverse conditions is the
hardest – and yet the most critical - skill to mast ...
On-board computers and the can line
The following on-board computers make up the electrical system of the diavel
and are connected with each other via the
can line (or network):
Master dashboard
Slave dashboard
Hands free (facilitated keyless start system)
Ecu (engine control unit)
Bbs (black box system or central elect ...