Well I know of 4 places that sell looms and 2 that I would recommend so a
"Where can I get a loom ?" or for that matter "where can I get ( name any part )" is a quick & easy reply
Where as "what size wire " requires one to actualy know the wire size in the right colours.
Now wire size is more than just the current capacity
There are quite a few variables like the diameter and number of the strands and the thickness of the insulation
Now this does not matter for the light switch because they are screw in connection onto ( hopefully ) a short piece of solder covered wire
However the right size for the bullet connectors is a different matter and is even more difficult depending upon if Bob wants to use crimped on connections where the external diameter of the wire is critical for a strong joint or soldered on bullets where the strand diameter is critical .
It is piss easy to say "divide the wattage of what is connected by your voltage then multiply by 1.2 to get the required amperage "

As previously mentioned I use scrap wire retrieved from old vans but the 10A wire is physically too small to be crimped to a modern bullet terminal as it will not clamp to the insulation and on top of that the strands are very thin and will work harden and fracture in no time flat if connected to a solder on bullet then we come to the push in dynamo & headlamp terminals where the strands in the 10A wire are so thin that they shear when pushed in
This is why I use uninsulated crip connectors that pierce the insulation then shrink wrap them before inserting into plugs /sockets.
Some thing that most WM20 owners are not willing to do as they value original apperance over functionality

Now if Bob had said "I am stranded in ( anywhere) and need urgent wiring help" he would have been swamped with replies.
But what he actually said is while the bike is off the road I would like to rewire it"
The inference is it was not URGENT so did not require an immediate responce .

YOU are the person who decided that Bob needed an urgent reply, not Bob
And making some effort to work out / find out basic capacity was good of you to do
Adding the insulting & abusive after note was not called for and says a large amount about your character .

Now Bob,
As you have now given us some more information hese is a few things I do

For the stop / tail I use 5 core trailer wire because it is compact and comes in a nice black loom
On my bike, that has a hinged plunger rear guard fitted, the trailer wire fits nicely & neatly inside the rib
When I did a bolt on guard I also used the same wire
I just make it long enough so the 3 pin plug I fit will hide behind the number plate bracket
The 3 pin plug saves continually joining the faded wires incorrectly in the dark
The conductors in trailer wire ( IN Aust ) are 18AWG which are too thin for a Lucas bullet
18 AWG is good for 5 A over about 8 foot ( 30 watt on our 6V bikes )
I use the same wire to go to the dip /horn switch on the handlebars ( like I said , not std wiring )
Again it is neat and comes in a nice black loom
The battery is also fitted with a plug that is handed and hidden under the saddle along with the 3 or 4 fuses
By fitting the plug I can then paint over the battery terminals with Liquid Electrical tape so there will never ever be any corrosion thus the bike will always get full battery voltage
Now 16 AWG is what is generally used on British bikes because it fits into Lucas terminals nicely
14 AWG can be "stuffed into them but you have to work hard to get them into the terminals
And 18 AWG needs a bit of heatshrink to compensate for the smaller diameter .
If it is automotive vinyal coated wire these should all should have 12 to 16 wires inside.
If they have more then they are audio cable and the wires will fracture and if fewer then it is AC wire and will not crimp particularly well

Now for the green & yellow dynamo wires.
They can be also be 16 AWG because for the maximunm dynamo output of 80 W (13 A ) 16AWG wire is good for around 4 foot
You could use 14 AWG it is a bit thicker and is good for 6 foot @ 13 A continious and that rarely happens

So if you are going for a single roll of wire go for 16 or 14 AWG

On 12 V bikes voltage drop is not so much of a problem but on 6 V bikes it is
Some time back between 2000 & 2010 I did an article on rewiring Cliff's WM20 for the club mag.
If I can dig it up I will post it

I usually fuse both sides of the battery plus the horn & stop light
For them I use ganged blade fuses that clip together gluded to length of thin flat bar that I drop down the seat frame tube so again they are out of the way and inconspicious
15A for the battery 5 A for the stop light & 10A for the horn
I do this because over the years short circuits in the stop lights seem to happen most regularly.
Not a problem on a magneto bike but a disaster if you have battery ignition.

Thanks again Ian for your help,Trevor too with this piece & the others who suggested ideas.
I'll be using Lucas bullet terminals so will probably go with Trevor's idea of 16AWG wire.
Probably just the one colour too.
As I said before, the existing wiring's pretty basic, just the Lucas diagram in everyone's manuals plus a couple of extra earths.
No electric horn, use that circuit for the brake light. I had a bulb horn but took it off when it stopped working- screamed obscenities are more emotionally satisfying.
The bike won't be going anywhere for a while but all its lights will work.

You can bend in the headlight sockets & the headlight shell ground socket but you have no alternative for the dynamo sockets and the std Lucas bullets do not fit in there .
In the back of my mind some one had some sort of a conversionfor them but I can not remember where I saw it and it is not on file .
FWIW I am on 9 BSA forums and get around 20 club magazines in various formats .
Back in the days of paper I would just photocopy stuff that should be remembered & shove the copy in the box
Now days there is a mix & different computers, phones & file formats etc etc etc so the idea gets remembered then the detail gets lost
The previous president had a similar M20 horn.
A farting flea would be the best way to describe the note
I can clearly remembe an inspection day and when the inspector hit the horn he looked at Mark asking "What do you do in an emergency ?"
The respons was F--- O-- C--- loud enough to be clearly heard in the factory unit next door as they came in to see what was happening expecting to see some sort of violnet confrontation.
The inspector shook his head, chuckled and ticked the horn box .
We all had a good laugh .
Those were the days !!!

Trevor
I know what you mean about the dynamo sockets. I have a small number of carefully preserved connectors for them. I'm not much good at soldering them.
Yes, those were the days.

['I can clearly remember an inspection day and when the inspector hit the horn he looked at Mark asking "What do you do in an emergency ?"
The respons was F--- O-- C--- loud enough to be clearly heard in the factory unit next door as they came in to see what was happening expecting to see some sort of violnet confrontation.
The inspector shook his head, chuckled and ticked the horn box .
We all had a good laugh .
Those were the days !!!...']

The local British bike dealer who used to do my MOTs always left the horn till last...He'd press it once and if it worked he'd say..'Quick, get it out of here while it's still working!'....:laughing:
I have an intense dislike for Lucas horns...They frequently wouldn't work on bikes I bought and I can rarely keep one going for 12 months, even the ones I've had reconditioned...
Generally I've found the 12volt versions to be longer lasting than the 6 volt ones...Ian

email (option): ian@wright52.plus.com

Interesting conversation, but I don't understand, why people, like Mark Cook, keep pushing for the very incredibly wrong products, have said this before, and will keep saying it, Mark, nothing personal, you do great work on stuff you make yourself, but some other stuff isn't worth to peddle, as it's so obviously wrong!

Anyway, I have said soooo much about this topic already, and I know it's not that easy, but Ian Wright gets it too, so about FB, there's sooo much desinformation there, and I try to follow up, and try to set it right, but sometimes it's just too much.

My 2 p. here.

Cheers,

Lex

email (option): welbike@welbi^^.n

Lex, not everyone has your tastes, all I do is offer options.
I don't agree with many things posted here, but I respect others opinions.

Mark

email (option): pes.sales@btconnect.com

Yep, I agree...I'm not concerned about absolute 'originality' as long as overall the bike looks the part with nothing that jumps out at the average enthusiast...
As most know from previous posts IMO once the bike has been restored it isn't original anyway, just a representation and it's a fact not everyone wants the same thing...There's no international standard after all....
For example,mine is now more or less 100% blasted stainless fasteners and fittings where cadmium would have been used...I think it's the best substitue visually and is certainly the most durable finish...Purists will hate it though..The wiring is a similar thing.....Here's one I made earlier as they say...Ian

email (option): ian@wright52.plus.com

During the years these bikes were built, the wiring looms would've been changed slightly, wouldn't they? Small detail differences between contracts, availability of components?

I gave in to forum bullying!

Black silicon wire and coloured heat shrink.

And so much of it!

Eight colours

If anyone else is in fear of the forum bullies, I have plenty of spare.



Mark

email (option): pes.sales@btconnect.com

Ah, rivet counters to people feeling being bullied 1-0

Thanks,

Lex

email (option): welbike@welbi**.net

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email (option): johankaroro@gmail.com

There's a Nuovo Falcone forum and a facebook page. Folks don't use the forum so much now, so it's more difficult to get up to date info from that and just about impossible to get info using facebook as a research archive. Facebook is pretty useless for that. This forum is easy to navigate and easy to get the necessary info on wiring using the SEARCH button....
I don't blame folks for not wasting their time on a query when the required info is obtainable at the press of that button. The depth of knowledge here is over and above any other forum I've used, and having several old bikes I use a lot of forums. Some are excellent and some so so, and it seems to depend on the age of the participants. Tribal Elders....