Starter motor circuit for Moto Guzzi LM  2 and 3 (most big models)

Beside the electric scheme underneath, it is usefull to have some sort of a diagnostig guidline. To start  with, a list of components,
- Starter button
- Primairy relay (30A)
- Fuse F1
- Battery
- Contact
- Starter motor unit with,
Starter motor
Bendix
Integrated relay
First aid,
What to do when your out there and m.th.rf.ck.r doesn't start?
Don't worry, your machine looks big, but you start it by pushing it in 2nd or 3rd gear. When gaining some speed, release the clutch and of you go, like a chitta, but more violent.

Diagnostic procedure

First check the fuse (Fuse 1 is the one at the bottom)

Battery sympthoms

Especially after a long stop of several months (3), the battery power of my LM2 is not really fit to power the starter motor. A battery in overall bad conditions will probably have the same sympthoms.
When pushing the starter button the primairy relay clicks and some times the integrated relay and Bendix as well, but there is no power to drive the starter motor. Most of the time the lights on the dashboard start to faint.

When continuing to try this, you can waste your primairy relay. (Own experience)

Charge the battery or use external power.
 

Starter Motor, Primary relay, Starter button or wiring

Symptom
You push your starter button and nothing happens, not even a click, but lights on dashboard shine. (When lights blink suspicious, check the contact breaker, but always first the fuses)

Start the procedure at the Starter Motor, use a wire to connect the integrated relay input to (+). The (+) is on the big-wire supply for the Starter Motor.
It doesn't work, have your Starter Motor checked
The motor turns, but the engine doesn't fire up. 
RUN/OFF button. I once had a group of big red ants (yes really) in the handle bar buttons. They were removing the "vaseline". When I switched the button to RUN it didn't make contact (first ants were coming out).
It works, continue

Use again a short-cut wire to connect pin 85 of the relay (usually White/Black wire) to ground.
It doesn't work, replace primary relay or check the wiring between the relay and starter motor and the feeding of the relay (check with a lightbulb or so).
It works, then continue

Take the connector at the handle bar. Short-circuit the RUN/OFF pins and use a wire to short-cut the starter button pins.
It doesn't work,
check the wiring to the primary relay

It does work,
check the resistance and functioning of the starter button.