Fitting a timing disc to a T3

Have a problem with ignition timing and want to use a mates timing disc (and his knowhow).
To use this I assume I need to remove the centre screw of the alternator.
can anyone give me some advice please on safe removal and replacement.

Any help much appreciated.

That centre screw pulls the rotor down on to a taper, and it usually takes a special tool before the rotor will come off of that. You could either clamp your disc on with the rotor in place or remove the rotor (if you have the tool) whilst timing up – the battery should sustain all of that happily with no charging going on for the duration.

BTW – I’ve never used a timing disc on a Guzzi. Someone else might want to chime in if there are easier ways to circumvent that. I’ve always worked with sticks down plug holes and the factory markings on the flywheel.

Use an allen key. It is that simple.
Do you not have the timing marks on the flywheel?
Or what cyclobutch has just posted.

Why do you think you need a timing disc?

I’ve never used one, including checking valve opening and closing angles of camshaft (admittedly a rough guide)

Ignition timing is even simpler, UNLESS someone has done something like had the flywheel off and put it back at the wrong angle relative to crankshaft.

EDIT: in my factory workshop manual it shows a timing disc being used with the whole timing cover taken off, also a special tool pointer is needed, screwed ACCURATELY in the correct positon into one of the timing cover’s fixing screw holes. So is not as simple as just taking the alternator rotor bolt out and plonking the disc on. Not if you want accuracy to the nearest degree. Which you should. Any cock-up in taking readings or interpretation of same will just create worse problems. Ergo personally would not touch the idea with a long pole, despite the best intentions of your mate.