TS175 Main Headlamp Switch - Daft Question

[Samurai]

Ok, I'm up for some ridicule with this question, I can take it . . .

I've stripped and rebuilt the engine and nearly finished rewiring the bike (the original loom was brittle and had already been removed from the bike) and am carefully going round trying to ensure continuity in the connections prior to hooking up a battery.

However, never having had a bevel single before and having bought the bike with the loom already removed, I have little idea as to which circuits the main switch on the top of the headlamp is actually meant to activate in each of its positions - can anyone give me a clue as to what should come on?

Sorry for the dumb question, but electrics are my least understood aspect of mechanics - wires are just there to keep the smoke in arn't they

[ducwiz]

Seems you work on your single without support of the workshop manual ...
Different electric system systems can b found in the various n/c Ducatis. Afaik, CEV and APRILIA are two of them, used in the 175 models.
http://s5.histats.com/stats/r.php?104172&100&58&urlr=&www.rpw.it/Files/Ducati_Motoleggere_Monoalbero_ManOff.pdf is a download URL for the italian manual (beware, 63 MB!). It contains at least 2 electrical schematics, showing also the function of the main switch.

cheers Hans

[Samurai]

Hi Hans,

Thanks for the link, but I do actually have a workshop manual for the 175TS, together with the wiring diagram. It's the original 6v system, 40w (three wire) alternator and battery.

However, although I have replicated the loom from the original and can follow the wiring diagram well enough to enable me to connect it up to the relevant terminals etc. (so I believe!), I am by no means an auto-electrician.

So when it comes to trying to work out exactly which circuits are meant to be active in each of the various ignition/main headlamp switch positions, when I have no experience of a running bike, it makes checking the relevant connections are working correctly a bit harder.

If you are able to tell me which warning lights and circuits SHOULD be operating in each position of the key/headlamp switch, that would be really helpful e.g. ignition switch on, headlamp switch first position anti-clockwise = this should be happening etc.!

I don't really want to stick a battery in and risk damage, without at least having a degree of confidence that things are connected up correctly

[Ventodue]

Is this what you're after? Actually from a 125 owner's manual, but likely to be the same.

[ducwiz]

OK, I suppose you have the Aprilia version. Please look into http://www.motoscrubs.com/Ducati_Electrics/Duc_Magneto.htm and confirm this; otherwise you might fail in understanding all the connections, and fabricating a non-fitting loom might be a result. Btw, the explanations in ventodue's OM match this circuit.
The booklet contains clearly perceptable, coloured circuit schematics, helping a lot to make the loom.
Finally, good luck with your electrics

Hans

[Ventodue]

Actually from a 125 owner's manual, but likely to be the same.

Update:
This is the proper description for the 175T & TS models, taken from the workshop manual. As Hans says, it's for what was originally the Aprilia wiring installation, referred to as "Fig. 22" in the text, a scan of which I've also posted below.

[Samurai]

Gents, you are both Stars, just what I was after!

The two page black and white wiring diagram is what I have a very poor reproduction of, but from the Italian workshop manual! It nearly made me blind looking at the broken type under a magnifing glass and translating it into English! I then spent a happy hour or so colouring in the lines so I could make some sense of it!

The colour version you linked to will help me double check my own version - all the electrical components are indeed labled Aprilia by the way.

So far eveeything is working out against both the diagram and the careful labelling and notes I made when replicating the old loom - fingers crossed!

The description of the switch operation that Ventodue supplied is just the thing I was after to confirm everything!

Many thanks to you both for taking the trouble to help me out, it is really appreciated .

Hopefully it won't be long before I can hook up a battery and try to start the little fella for the first time in about 20 yrs!

[CaptonZap]

Is my eye sight going bad, or is there no voltage regulator shown?
Is this one of those transformer coupled regulation schemes that Ducati used?
But no, I see no transformer.
Is it one of those "We'll make the output real close to the draw, and if you don't keep the RPM's up, you will slowly drain the battery" arrangements.
And people throw aspersions at Lucas.

CZ

[Ventodue]

Is my eye sight going bad, or is there no voltage regulator shown? <snip> Is it one of those "We'll make the output real close to the draw, and if you don't keep the RPM's up, you will slowly drain the battery" arrangements.

As I understand it, yes . Here's Ducati's own explanation of how it works. The translation into English isn't perfect, but if you change words like "commutation" to "switching" it becomes clearer.

As they say:

1. The alternator never wacks out enuf juice to over-charge the battery. So no worries there.
2. Even in the worst case, there's at least 10 hours of 'Running around with the lights on' time in the battery. Plenty enuf for the average rider.
3. And if the battery does ever go flat, who cares 'cos the bike don't need a battery to run in the first place.

And remember: for the buyer of the time, the critical thing would have been, "Will the damn thing start?" And that's what Ducati were trying to ensure, rather than fussing over much about 'extras' such as lights.

. "Life was so much simpler then".

[CaptonZap]

Yup, sounds like like Joseph all right.

CZ