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 devicesHow to start the engine
With the motorcycle off and the dashboard on, the on/off switch is turned to
"run off"
With the motorcycle and dashboard on, the on/off switch is turned to "run
off".
To start the engine, simply push the on/off switch up to "run on" and press the
black start button.
...
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 ...
Checking and overhauling the components
Clearance between the clutch drum and friction plates
Insert a friction plate (e) in the clutch drum (f) and measure the clearance
(s) with a feeler gauge.
Clearance "s" must not exceed 0.6 Mm.
If it does, renew the plates and, if necessary, the clutch drum.
Overhaul of the clutch plat ...