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 devicesDisassembly of the gearbox shafts
Place the shaft in a vice in such a way as to facilitate the disassembly
operations.
Important
Take care not to invert the positions of the shims on reassembly:
this would potentially lead to jamming when using the gear selector control,
making it necessary to reopen the engine
crankcase.
D ...
Refitting the rear sprocket
Check the cush drive bushes (6) condition and, if necessary, replace them by
removing them from the flange.
Refitting is the reverse of removal.
Apply recommended grease on the rear sprocket flange (5) external diameter.
Place the rear sprocket flange (5) on sprocket (17) by inserting it ...
Checking valve lift
Set the engine to the configuration described for the "checking and adjusting
the valve clearances", previously indicated.
Position the tool 88765.1518 On the cylinder head: the part marked "a" should be
on the intake side and the part
marked "s" should be on the exhaust side.
Seat the pl ...