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 devicesRemoval of the exhaust system
Remove the silencer, as described in the paragraph "removing the silencer" of
this section.
Loosen the screws (28) and remove the exhaust by-pass valve cover (27).
Turn the exhaust valve pulley (a) to facilitate the throttle cable (25)
output.
Release the end fitting (b) of the cable ...
Stop light not working
Fault codes
Dds: stop light diagnosis -> stop light error (generic stop light malfunction
indication).
Dashboard: the error "stop light" is shown on the service display. The eobd
warning light activates.
Wiring diagram
Db dashboard connection, bbs bbs unit connection, a front brake ...
Checking the battery charging system
To check the current flow of the recharging circuit, use the "dds" diagnosis
instrument, which is equipped with an
inductive clamp-type amperemeter: refer to chapter "testing the battery charging
system", sect. 6 - 11
With the dds diagnosis instrument you can determine the engine rpm required ...