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Ok new questions. I wasnt sure if I should start a new thread or continue this one. I'm on to finishing up the wiring. I went 12v with a newer model 12v stator. I'm using a wiring diagram I found online that someone made while restoring their 1955 6t. 1st question is I wired my prs8 switch and I'm worried about the strain on the wires from vibration and turning. I feel i should mount a strain relief. Where should i mount one? Second question. I have a 6v ammeter that I jumped each side with a 6" jumper wire. I was told to do that because ammeters commonly fail and while jumped it will keep running with a failed ammeter. I was also told if the ammeter is jumped it will read half its value. Is this fine jumping a 6v ammeter on a 12v system? Third and final for now question. I'm using 2 6v cyclon batteries wired to make 12v. These batteries fit nicely in the lucas battery box. The problem is the batteries use spade connectors and not traditional bolt on connectors. I was thinking about using 2 battery tender cables. 1 to attach to the battery and 1 to solder to the harness. In my mind the benefits are an ability to quickly unplug the battery to charge, and the tender cable would have a built in fuse holder on the harness side. Do you see anything wrong with doing this? Thanks again for the help
 

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1957 TRW wiring

Hi,

new questions. I wasnt sure if I should start a new thread or continue this one.
As a rule, new subject, new thread - brings the new subject to the attention of people who aren't going to read a thread - particularly a long one - about, say, the primary, to see if there's an electrical question somewhere in it.

prs8 switch
worried about the strain on the wires from vibration and turning. I feel i should mount a strain relief. Where should i mount one?
What do you mean by "strain relief"? Turn the steering lock-to-lock while watching the wires to the switch; if you see the wires pulling on the switch connections, the wires are too short, make 'em longer. One thing I always do when wiring a bike I haven't wired before is to make a loop about the diameter of a finger in each wire that goes from/to anywhere on the forks from/to anywhere on the rest of the bike. Once the bike has been used for a bit, if the loop made the wire too long, it's easy to cut off a bit and crimp on a new terminal; but if a wire's too short to start with, it's a pita to replace (no, don't use butt splices ... ;)).

I went 12v with a newer model 12v stator.
You are confused.

There isn't any such thing as a "12v stator" (a seller might describe one as such but all that means is the seller knows as much about electrics as I do about quantum physics :rolleyes:). Stators - alternators - generate AC - Alternating Current; specifically AC Volts vary wildly depending on alternator rotor rpm and the electrical 'load' (ignition, lights, etc.) on the stator.

AC is rectified to DC - Direct Current - by a rectifier. If the bike has a battery, this must happen; AC fcuks batteries. You can have AC ignition with (a) special coil(s) and incandescent bulbs will work with AC, but no battery; ime far more trouble than it's worth just to save a rectifier.

DC Volts - usually 6V or 12V - are set by the regulation. You can couple any regulator to any alternator so, as I say, there isn't any such thing as a "12v stator".

Britbikes made before the mid-1960's had a very crude form of 'regulation', depending how the ignition and lighting switches (combined in the PRS8) were set by the rider, connections were also made (or 'unmade') to direct the output of different alternator stator coils - say, all six coils were 'connected' when the headlamp was switched on, but only two stator coils were 'connected' when only the ignition was on. Although the electrics themselves are easy (if time-consuming) to test, the system suffers because the understanding of the underlying principles of this type of 'regulation' is generally poor. :(

From the mid-1960's, electrical regulation on Britbikes was by one (later more) Zener diode(s). At the time, Zeners were only for 12V, so mid-1960's-on Britbikes with batteries have 12V DC electrics. If the bike is fitted with only one Zener diode, it must be connected 'across' the battery; i.e. you must be able to trace a fully-insulated wire from the Zener's insulated terminal to one battery terminal and, ideally, a second insulated wire from the Zener's mounting to the other battery terminal (using the bike's structural components as electrical conductors is unreliable).

Modern regulation is normally combined with rectification in one 'box', hence 'regulator/rectifier' aka 'reg./rec.' A feature of these is the electronics 'sense' the DC 'load' - ignition, lights, battery charging, etc. - and only rectify enough AC to satisfy this 'load', turning any excess from the alternator into heat.

I have a 6v ammeter
a 6v ammeter on a 12v system
Uh-uh.

Volts ("V") and Amps ("A") are different if inextricably-linked electrical units.

An "Ammeter" measures Amps (a Voltmeter measures Volts), two different units/measurements, two completely-different meters, they are/would be connected entirely differently to the bike's electrics.

The original alternator on a TRW was a feeble device even when new, I suspect the Ammeter can measure +/- 8A with a central zero?

I jumped each side with a 6" jumper wire.
:umph The jumper wire only has to connect the Ammeter's two terminals, which are only about an inch apart?

I was told to do that because ammeters commonly fail and while jumped it will keep running with a failed ammeter.
That's one reason.

The other can be - depending on the new alternator stator - an original Ammeter's range is too small; with a jumper wire conduction half the alternator output/draw from the battery, you can continue to use an original Ammeter.

2 6v cyclon batteries wired to make 12v.
problem is the batteries use spade connectors and not traditional bolt on connectors. I was thinking about using 2 battery tender cables. 1 to attach to the battery and 1 to solder to the harness.
:nah

Firstly here, unless you are very, very good at soldering, I'd advise against it. Problem has always been that, the further solder runs down a wire's conductor, the stiffer the conductor is when the joint cools then the more prone it is to vibration damage some time in the future. :( Second problem is you can't see how far solder has run down the conductor without destroying the joint :Darn and, if it cracks in the future, you get an intermittent fault that's :arghh to find.

Secondly, if you are using two separate 6V batteries, in order for them to supply 12V, they must be connected 'in series':-

. the single harness negative (-ve) wire connected to one battery's "-" terminal;

. the single harness positive (+ve) wire connected to the other battery's "+" terminal;

. the two battery terminals without harness wires connected together.

Why not buy proper spade terminals, wire and crimping tools? As you're in the US, look at British Wiring. I appreciate the tools aren't the cheapest but a) good tools never are; b) cheaper that'll still do a reasonable job are likely on eBay.

In my mind the benefits are an ability to quickly unplug the battery to charge, and the tender cable would have a built in fuse holder on the harness side. Do you see anything wrong with doing this?
Your thinking concerns me. If you're fitting a new alternator stator, why isn't it capable of keeping the batteries charged when you ride? That said, how much any stator can generate depends in part on the rotor's magnetic strength, that attenuates with age and an original '57 alternator rotor is now 61 years old ...

I'm using a wiring diagram I found online
No offence intended ... but your post gives the impression you know as much about electrics as I do about the aforementioned quantum physics. :) No problem, we all have to start somewhere on any new subject, but I suspect you could do with more help than you know. If so, start by posting the link to the wiring diagram, and telling us what this "newer model ... stator" actually is?

Hth.

Regards,
 

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Discussion Starter #3
Haha electronics are for sure not my strong point. I should have known better then writing "6v ammeter " most suppliers from my experience describe their product as 6v or 12v probably describing the system the part goes to. Maybe to help the electrical impaired like me haha. I'm using a lucas 16 amp 200 watt single phase stator and a new rotor and a podtronix regulator rectifier. The regulator helps me simplify the wiring going to the prs8 switch. The diagram I'm using is this guys modified diagram on the second to last page

https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.britbike.com/members/roger_dunnick/My_1955_Triumph_6T_sep2016.pdf&ved=2ahUKEwi-t9Od9tLeAhWDnoMKHS_pBe0QFjAKegQIABAB&usg=AOvVaw0J-7yTsrCIpB5CXCLpsGxb

If I did it correct this link should work. I used a 6" length to jump because it was just easier to work with. The eyelets length to make the short jump left a tiny stiff wire between the two. Now it kind of loops and connects the terminals of the 8 amp ammeter.

The reason I brought up the connection of the battery was because it fits in the rubber lucas battery box. I do plan on using the correct spade connectors inside the box. I wanted to put a connector hanging out of the box so when the lid is on and it is clamped in the carrier I can still unplug the battery without tools. I'm afraid of taking the harness connections all the way inside the battery box in case there is an emergency and I have to unplug it.

Thanks for such a thorough post. There's a lot of information in it I appreciate it. I have always soldered connections in place of crimping them. Your clear logic has me second guessing my use of solder. Thanks again for the post.
 

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Hi,

Thanks for such a thorough post.
Always pleased if I helped. :)

using a lucas 16 amp 200 watt single phase stator and a new rotor
Be aware this is somewhat dubious.

"lucas" in this context isn't the 'original Lucas' that made your bike's original electrical equipment. Aiui, that "Lucas" was taken over in 1979 by a company called TRW. In 2014, TRW licensed the "Lucas" brand and packaging to a company called Wassell, who have made some parts for our old heaps for many years, the vast majority of which have ... uh ... quality issues ...at one time or another. Wassell now market electrical equipment using the "Genuine Lucas" branding, rather than the "Wassell" name.

If you haven't fitted the new stator and rotor on the bike, I advise at least a test fit as soon as possible, so any problems found hold up collective progress as little as possible. 'Original Lucas' specified the '62-on rotor-crankshaft fit as 0.7500"-0.7505"; even if your bike requires an adaptor between a new rotor and the crankshaft, nothing should be either loose or more than a 'half-thou.' (0.0005") interference-fit.

Has 'Wassell Lucas' quoted any check-clearance between rotor and stator? 'Original Lucas' specified between 0.008" and 0.012" for single-phase stators; whatever is specified, you should be able to measure it all the way 'round between rotor and stator, and the check should be repeatable having moved the crankshaft/rotor to three or four different positions relative to the stator.

If you have any difficulties with clearances, try to find a local engineer or machinist willing to measure the offending parts - either crankshaft OD/rotor ID or rotor OD/stator ID.

There is some doubt about the "16 amp". Physically, 'Wassell Lucas' stators and rotors are pattern copies of 'original Lucas' stators and rotors; your "16 amp" stator is a physical copy of the RM23 made between c.1969 and 1978. 'Wassell Lucas' stamp "16A" (and "20A") on its single-phase stators but I've not been able to find actual confirmation that the "A" really does stand for "Amps" as many assume. The other problem is I can't find anywhere that 'Wassell Lucas' states the rpm these "Amps" are produced - e.g. 'original Lucas' used to specify "@ 5,000 rpm", and rated the RM23 for 14.5 Amps @ 5,000 rpm; in theory, it might produce 16 Amps ... but the rotor has to be spinning at about 8,000 rpm ...

That said, it should produce a lot more power than your TRW's original alternator ...

and a podtronix regulator rectifier.
:thumb

Hmmm ... how can I put this politely ...? This is over-complicated cobblers. You might find some help reading the .pdf but, afaict, he's missed one almost-overriding principle:-

K.I.S.S.

Keep It Simple Stupid

1. Passing the alternator Amps through the PRS8 (between switch terminals #13 and #2) is just about acceptable if, like the .pdf author, you're using the original feeble alternator and you don't really know what you're doing; ime, passing the Amps of a modern alternator through a sixty-year-old switch is A Dumb Idea. Although the author mentions both the Lucas Motor Cycle Electrical Equipment Service Manual and various Triumph Workshop Manuals, he has simply not understood the information there, he hasn't grasped the reasons behind the changes made first when Lucas replaced the PRS8 with separate 88SA switches, then when Zener diode charging control was introduced, leading to the replacement of first the 88SA Ignition Switch and then the Lighting Switch.

2. You've posted you're using a (Podtronics) combined regulator/rectifier. The author has incorrectly-labelled the Ammeter terminals "+" and "-". They aren't (they can't be); on that diagram, they're both "-". Simply, the Podtronics Black wire should be connected to the same Ammeter terminal as the Brown/White wire (if the Podtronics Black wire isn't long enough, extend it (see "Wire" below) to the Ammeter terminal).

3. The original reason for a Brown/White wire from the Ammeter to terminal #2 was it connected the battery (through the Ammeter) directly to the Lighting Switch for 'parking lights' - pilot and tail lamps on but ignition off - dunno about other countries but GB has long had a legal requirement that anything left on an unlit (no streetlights) road at night must be lit front and back. Aiui, the US doesn't have this requirement so, having connected the Pod Black wire to the Ammeter as above, connect the Brown/White from the Ammeter to switch terminal #13 - i.e. into the Ignition part of the PRS8; then only power used by the lights will need to use the connection between Ignition and Lighting parts.

I used a 6" length to jump because it was just easier to work with. The eyelets length to make the short jump left a tiny stiff wire between the two.
Ye-ea-ah ... I understand your basic reasoning but ... between the headlamp, PRS8, Ammeter, Uncle Tom Cobbley an' all, there isn't much spare room in that nacelle/headlamp shell. It'd be a shame to find, when you try to fit the headlamp, it don't fit 'cos your "easier to work with" wiring takes up too much room ... or gets squashed and cut between two components causing a short?

connection of the battery
I wanted to put a connector hanging out of the box so when the lid is on and it is clamped in the carrier I can still unplug the battery without tools. I'm afraid of taking the harness connections all the way inside the battery box in case there is an emergency and I have to unplug it.
The thing for "an emergency" is called "a fuse". ;)

However, I don't understand "unplug the battery without tools"? Why? If the battery connections were more conventional, you'd need a screwdriver to dis/connect the battery. By all means have connectors to make life easier. But beware of making any conductor out of short bits of wire and multiple connectors; if anything electrical is going to cause problems by falling apart, corroding, blah, it's connectors, not wire.

Fuses
This:-

Now a lot of Triumph wiring harnesses get burned up. Typically it is the red ground wire from the battery and the damage extends right through the harness. Why didn’t the fuse protect the harness?

Now some of you will immediately recognize the problem and suggest that the fuse should have been put on the ground side of the battery. Well, in 1966 they did just that, but they discovered: If the fuse failed while the bike was running the bike would keep running and damage the rectifier. The next year they changed the harness with the fuse on the feed side of the battery.

Uh-oh! So much for going against convention and standardization. For the 12-volt upgrade, I changed my mind and decided to place the main fuse in the hot (negative) terminal’s lead.
... is twaddle; again, the author hasn't understood what he's doing:-

. Far-and-away more common than "if the fuse failed while the bike was running the bike would keep running and damage the rectifier" is something metal touching the battery -ve terminal itself and a part of the bike, all which is connected to the battery +ve terminal by the Red wire. The "something metal" could be the seat pan bending (see recent thread https://www.triumphrat.net/classic-vintage-and-veteran/942446-burnt-positive-earth-wire.html), a loose tool or other piece of metal; even, a while ago, an owner was charging the battery on the bike and the seat closed on the charger terminal attached to battery -ve ... :Not again In all cases, the short then wasn't through any fuse connected to battery -ve ... But, if the main fuse in in the one single Red wire attached to battery +ve ...

. The author's wiring diagram you're intending to use doesn't have a "rectifier", it has a modern reg./rec., and you're intending to use a Podtronics reg./rec. If you connect the Pod Black wire to the same Ammeter terminal as the Brown/White wire (as I've advised above) and the Pod Red wire directly to battery +ve, "if the fuse [connected to battery +ve] failed while the bike was running", it is simply impossible "the bike would keep running and damage the rectifier".

. If you connect the Pod Red wire directly to battery +ve, because the Pod Black wire is connected to battery -ve through the Ammeter and Brown/Blue wire, there is the very tiny chance a component inside the reg./rec. could fail 'closed' and cause a short. Because I've been given other ... uh ... less well-made ... reg./rec. to fit, I fit a fuse in the Red wire between battery +ve and the reg./rec.

Simply, if you fit fuses connected to battery -ve (in this case), they should be positioned in the harness and rated to protect individual components or small groups; a short in the component or group should then cause the lower-rated fuse to blow rather than the main fuse attached to battery +ve. The main fuse attached to battery +ve is the 'backstop', when everything else hasn't stopped a short-circuit.

Wire
The information about wire in the .pdf is ... :Huh:-

. The .pdf author adapted a modern replica harness for a much later bike. The best modern replica harnesses are made with the same wire sizes as listed by British Wiring on http://www.britishwiring.com/PVC-Wires-s/67.htm and the vast majority of wires are "14 Strand PVC Wire "18 Gauge" (C114)". Be aware that, irrespective of "Gauge" (AWG) information included by BW, the wire is metric (each strand is 0.30 mm OD, 14-strand has a total conductor cross-section of 1 sq.mm., 28-strand is 2 sq.mm., etc.).

All of the wires in the harnesses are the Imperial equivalent of 14/0.30
... in the .pdf is tosh; when I started my first rewire in 1982, with a Lucas shop just down the road, wire sizes were metric; neither the Imperial wire size in the bike's original 1975 Lucas-made harness nor the terminals to fit were available.

. Because the .pdf author adapted a modern replica harness, it's possible he experienced difficulty fitting crimp-on bullet terminals during alterations. I don't know where 'Wassell Lucas' have their replica harnesses made (China?) but, regrettably, I have come across wire sizes on different Far-Eastern-made modern replica components that standard metric-ID Crimping Bullet terminals won't stay on; the .pdf author then incorrectly extrapolating this difficulty to his statement?

. Ime, the only available crimping bullets of that type have metric ID. Fine as long as you're fitting 'em to corresponding metric wire - the ID of each different metric bullet type allows it to be slid over the corresponding metric conductor, then the correct crimping tool crushes the ID sufficiently to keep the bullet on the wire under 'most' circumstances. However, if the conductor is some peculiar slightly-smaller size ... :Not again

Red wires
Not shown in any wiring diagram, but more and more common in later 'original Lucas'-supplied harnesses, the Red wires form a network connecting electrical components directly with battery +ve. This is far more long-term reliable than connecting components to sundry bits of bike and leaving the connections between the bits of bike and battery +ve to breaks in paint, powder-coating and corrosion (none of the last three being electrically-conductive).

The .pdf author wrote he used 16AWG wire to make additional Return wires between components and battery +ve. Again, likely just about ok with an original 1955 alternator but not with the modern type you're using and wires common to several circuits. When you get to fitting the harness, or when you're ordering additional wire and connectors, I'll be happy to detail how I arrange the Red wires' network.

"Ground"
Connected with the Red wires is the term "Ground", aka "earth".

Do not get hung up trying to understand others' 'explanations'. Problem is, "ground" aka "earth" isn't something that actually exists in DC electrics; the .pdf author has missed this fundamental in his general (mis)use of the term. :bluduh

DC electrics are very, very simple. Every component has just two conductors - Supply from battery -ve (the multi-coloured wires on your bike) and Return to battery +ve (the Red wires on your bike). Anything else is bull. :rolleyes:

Relays
I suspect not something you know about, but could become important if you plan to use some of the new alternator's power on better lamps and similar.

As I've mentioned above, the bike's PRS8 switch is old - 61 if it's original to the bike. It might still work switching, say, the original low-powered headlamp but, if you fancy a modern quartz-halogen, the switch connections might struggle to transmit the extra Amps directly. :(

Relays are remote switches. In the example of the headlamp, you could hide away two relays (one for main, one for dip), supply them with another wire connected at the Ammeter (so the Amps being used by the headlamp still show) and connect one relay to headlamp main, the other to dip.

Then the bike's original switches (handlebar dipswitch supplied through the PRS8) are connected to the relays, not the headlamp bulb itself. The advantage is the bike's original switches are switching just the relays, which require a few milliAmps, not the full headlamp Amps. :thumb

Hth.

Regards,
 

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Wow! It takes a special kind of person to know electronics at your level. It has always been something I just take for granted. I know it would be easier to have a professional wire the bike but I feel the need to do it myself. This is how we learn. I will sit down this week and read through your posts and try to come up with a solution. I may print off the wiring diagram and a modify it the way I think you are trying to get me to understand. Maybe then I can post a pic of the new diagram and you can tell me if I got it. But for tonight I have to take a break from it and do something mechanical to ease my mind haha. I know it's not much thinking for you but it's new to me so its gonna take time to beat it into my noggin.
 

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By the way I am using a NOS wiring loom for the trw. It matches all the color wired as the diagram we have been talking about. Except a couple colors. Those colors I couldn't tell you exactly right now because I'm at work. I think however it is one wire is brown/ white in the diagram and mine is solid brown. Also one is buff in the diagram and mine is purple. Either way you can tell easily which wire im supposed to be dealing with.
 

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Hi,

Wow! It takes a special kind of person to know electronics at your level.
Kind of you to say so but this level is plain old electrics rather than electronics, and my electrics experience is mainly just that, just I started out on Britbikes nearly forty years ago. :)

Ime, the most important thing when working on (any bike, vehicle) electrics isn't so much knowledge as simply being able to work logically; e.g. if you lose your way in a wiring diagram, start again at the battery. If nothing else, electrics (and electronics) are logical.

The second-most important thing when working on Britbike electrics is the knowledge to know what's simple, basic electrics and what's waffle and bullsh1t - as you might've gathered, one of my pet hates is the confusing drivel spouted and regurgitated about "ground" (aka 'earth'). :bluduh

I know it would be easier to have a professional wire the bike
We-el-ll ... imho snag is Britbikes anything like ours haven't been made in well over thirty years, so how does anyone qualify as "professional"? They might work on modern bikes, cars, etc. but there's nothing that says they then know anything about the compatibility of modern electrics and electronics to a sixty-year-old bike. And, if the job comes back to you wrapped in harness tape, you aren't going to know 'til something goes t1ts-up?

I feel the need to do it myself. This is how we learn.
:agree :doublethumb

I may print off the wiring diagram and a modify it the way I think you are trying to get me to understand.
:thumb Sounds like A Plan. Then, as you say, post your modified diagram.

do something mechanical to ease my mind
I remember putting off my first rewire for ages, putting up with an increasing number of electrical niggles. :( Once I did start, everything did quickly become much clearer (albeit luckily for me, in those BI (Before Internet) days, in GB, Lucas still had a chain of shops with proper auto-electricians, I had one just down the road from where I lived at the time and the electricians didn't mind answering stupid questions); however, I'm still faintly amazed it all worked first time ... :whistle

using a NOS wiring loom for the trw. It matches all the color wired as the diagram we have been talking about. Except a couple colors.
When you look at it closely, it'll be interesting to see if the wire colours differences tell how 'old' the harness is. By this I mean whether the differences match '57 (late 1950's) colours or what they morphed to later - e.g. whether the wires attached to battery -ve are Brown or Brown/Blue.

Reason I say this is I've seen "NOS" - New Old Stock - isn't a single definition when it comes to wiring harnesses. Your bike's a '57 but certain militaries continued to use TRW's at least into the 1970's; so, while 'original Lucas' would've continued to make new (now "NOS") wiring harnesses, ime wire colours were often changed to whatever was the contemporary standard when a given harness was actually made.

No rush but, as well as the wire colours differences, if you have time to take and post a couple of close-up images of the harness's spade and bullet terminals, that might help with dating the harness.

Also when you have time, another thing to look closely at is the thickness of the wires to be attached to the battery and the original rectifier. Reason I suggest this is, while Lucas often made these 14-strand wire in harnesses for 'civvy' bikes - where cost was considered important, the greater Amps in 6-Volt electrics can warrant 28-strand for those wires, so it might've been used in harnesses for a military model.

Regards,
 

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I found these for you and took a picture. I have been working slowly on this bike for 5 years. Not because I'm a slow worker but because I would wait long amounts of time for the absolute best price on genuine NOS parts. I saved a lot of the tags on the boxes to add to a folder of the bikes history.I found these being pressed flat between a Harley Davidson book haha. Both wires to be attached to the battery are solid brown. The wire labeled buff in the diagram is also purple.
 

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It was always a cool experience unwrapping the part. Most of the parts haven't been exposed since they were wrapped in the late 50s. I bought a primary cover and like most parts was covered in cosmoline. After removing the cosmoline I was always amazed at the brand new 60 year old part that looked like it was a day old. All parts where wrapped in a heavy wax paper and just drenched in cosmoline. Sometimes to the point you couldn't recognize the part. Nos parts are getting harder and harder to find at a reasonable price. I'm glad I started collecting when I did. Only thing that bothers me is putting heavy miles on this bike without fear of where I'm gonna get that bushing or that connecting rod or that tappet.
 

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Hi,

Both wires to be attached to the battery are solid brown. The wire labeled buff in the diagram is also purple.
:thumb This plus the labels picture is excellent clarification.

The wire labelled "Buff" in the diagram, that's Purple in your TRW harness, is the one between PRS8 terminal #13 and the original rectifier position? If so, that colour change appears in wiring diagrams between the up-to-'55 and the '56-'62 manuals (changing to Brown/White '63-on). I've a suspicion the '55-'56 change from Buff to Purple could've been to avoid assembly confusion between what's essentially two different shades of brown; :Darn that the .pdf author's bike was a '55 and he adapted a harness for a mid-1960's Triumph could be one reason he missed the '56-'62 use of Purple.

In an earlier post, I advised checking the thickness of the (Brown) wire between battery -ve and ammeter, the (Brown/White) wire between ammeter and PRS8 and now also the Purple wire between original rectifier and PRS8; [EDIT] even if any of these are "40/36" (40 x 36SWG strands), they still wouldn't be rated high enough - 10A? - for your new alternator.

Because those wires and connections could carry the alternator's full output under certain conditions, I still strongly advise connecting/extending the Podtronics Black wire to the same Ammeter terminal as the (wiring diagram) Brown/White, then connecting the latter to terminal #13; however, up to you which wire colour(s) you use to do that. :) For the same reason, I wouldn't have an external wire to terminal #2 - unless you specifically want to keep the 'parking lights' option - as #2 has the internal connection from terminal #12.

Handily, British Wiring sells Brown, Brown/White and Purple (but not Brown/Blue) in something they label 25 Amp Thin Wall Cable. This has the same 28/0.30 conductor as 28 Strand PVC Wire "14 Gauge" (C128) but, thanks to a different plastic insulation, while the latter is only rated for 17.5A, the "Thin Wall" is rated for the aforementioned 25A, similar to the even-thicker 44-strand mentioned in the .pdf. :thumb Fwiw, in GB, we can get "Thin Wall" in more colours than British Wiring hold; I've used it for a couple of decades without any problems.

The harness's original bullet terminals are soldered to the wires? If so, ime these joints are much less likely to be a problem than home-soldered joints - afaict, Lucas swapped to crimping terminals sometime in the early 1960's, possibly because they could then use less-skilled workers and save money compared with skilled solderers.

Btw and otoh, modern snap connectors are (should be) fine on original bullets, original and modern are (should be) the same 3/16" OD. :thumb

Finally here, digressing but hopefully not loading you with useless information, the common Brown/Blue in Lucas motorcycle harnesses seems to have been a late 1950's aberration by someone in Lucas? :) In 1963, the Lucas wiring colour codes were adopted as a British Standard (BS Au7) and plain Brown is listed as "Main battery feed" or similar while Green/Purple is between brake/stop lamp(s) and switch(es); seems, when there was some late-1950's desire for different-coloured wires at the brake/stop lamp switch, instead of leaving Brown between battery and switch and changing the wire colour between switch and lamp, the wire colour between battery and switch was changed? :umph

Hth.

Regards,
 

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Discussion Starter #11
No time this weekend to work on the bike but I did stop to measure the wires the harness uses. It appears the wires all consist of 40 individual strands measuring 0.19mm each. I'll start by reading up on SWG. Next I'll order up the correct guage wires you mentioned. The method you mention about taking individual earth wires to each component is something I would like to learn more about. All the leads red in color just bunch up back on the positive terminal of the battery instead of using the frame? What guage of wire should be used for that?
 

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Hi,

I'll start by reading up on SWG.
https://en.wikipedia.org/wiki/Standard_wire_gauge. As well as wire, before metrication, British industry also used SWG for things like metal plate and strip thicknesses.

It appears the wires all consist of 40 individual strands measuring 0.19mm each.
Intriguing ...

"0.19mm" likely actually makes it 36SWG (0.193 mm.), and I knew 40 strands of 36SWG as an old Rolls-Royce wire size. Risking stating the obvious, the advantage of a higher number of thinner strands is the complete wire is more flexible. The downside is greater cost - nice to know where some of British taxpayers' money was going in those days. :)

I knew Lucas might've used thinner strands in much thicker wires - someone once posted he found 34SWG in an electric-start Commando's starter cables - but, as I say, I never realised Lucas used what I knew as old Roller wire. That's today's "You Learn Something New Every Day". :)

If my metric cross-section area calculation is correct, 40/36 is 1.17 sq.mm. If so, you want to use crimp-on bullet terminals and ones intended for 1 sq.mm. conductor will fit, when crimped, the extra conductor cross-section should make very firm and long-lasting joints. :thumb

I'll order up the correct guage wires you mentioned.
If my metric cross-section area calculation is correct, "40/36" would likely be rated for 10A, so still not enough for wires that might have to conduct the full new alternator output; I would still use 28/0.30 for those wires, either with "Thin Wall" or 'normal' PVC insulation.

The method you mention about taking individual earth wires to each component is something I would like to learn more about. All the leads red in color just bunch up back on the positive terminal of the battery instead of using the frame? What guage of wire should be used for that?
While using the frame (any part other than wire) as an electrical conductor has cost-saving attraction, it isn't long-term reliable - it's hard to seal wire or components' connections - they'll then corrode - and, if more than one cycle or engine part forms the conductor, the joint(s) between are impossible to seal so they'll conduct reliably long-term.

Digressing slightly, I'm more used to dealing with 'civilian' bike harnesses, their over-riding criterion was cost - the bike maker always wanted to pay as little as possible. By the early 1970's, those harnesses' Red Return wires' network is about as good as ever - the bike makers had been persuaded to pay for the reliability but, by then, the British motorcycle-making industry had bigger problems than adding the last few components to the network. :(

So, when I build a harness:-

. The Red Return wires' network starts with two snap connectors that take four wires in each end, one in the headlamp shell/nacelle and the other under the seat (because most electrical components are in those areas).

. I connect each individual component's Return wire, or one from its mounting, to the nearest snap connector, but leaving at least one "way" clear in each snap connector; wires from individual components/mountings are the same size as individual components' Supply wires.

. I connect the two snap connectors together with two lengths of 28/0.30 thinwall, either joined together at a ring terminal on a head bolt or stud, or at a snap connector above the head bolt/stud, with another short wire from that snap connector to the head bolt or stud.

. On a non-electric-start bike, I join the snap connector under the seat to battery +ve with another length of 28/0.30 thinwall through the main fuse.

This works equally-well with earlier 'civvy' harnesses, because the earlier they are, they have even fewer Red Return wires as standard. However, your TRW harness might've been built better, with it containing Red Return wires for more (all?) components, "bunch[ing] up back on the positive terminal of the battery" because each individual component Return wire runs through the harness to there?

In your place, first I'd be inclined to try and identify how many individual components the harness has Red Return wires for already. If it turns out to be all components, :thumb the only mods. to fit a main fuse to battery +ve would be to separate the wires from the existing battery +ve (ring?) terminal, terminate them with - say, bullets to be fitted into a snap connector? - then connect the snap connector to battery +ve with a new 28/0.30 / 14AWG wire through the new fuse. However, these last modification suggestions are tentative, depending on what you identify in your TRW harness.

Hth.

Regards,
 

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Discussion Starter #13
Ok it's all coming to me. I'm starting to get all of this. My harness has no red wires. Instead it had one short length of wire to earth to the frame. I'm about to order my wires but wanted to ask a couple questions. There was no red for the thin wall wire rated at 25 amps. Would the 44 strand PVC wire be to think to work with or should I just pick a different color of the thin wall? As for each of the red earth wires coming off of the components in the nacelle such as the pilot light. Should they be the 25 amp as well or will the 14 strand do. I understand the main stretch between the snap connectors should be the thin wall 25 amp. I'm just talking about the wires that go from the snap connectors to the components. Thanks again for the help.
 

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Hi,

I knew 40 strands of 36SWG as an old Rolls-Royce wire size. Risking stating the obvious, the advantage of a higher number of thinner strands is the complete wire is more flexible.
I never realised Lucas used what I knew as old Roller wire.
your TRW harness might've been built better,
harness has no red wires. Instead it had one short length of wire to earth to the frame.
:SadSigh You couldn't ever leave a gun around Lucas - all the harness designers'd be on crutches or in wheelchairs ...

I understand the main stretch between the snap connectors should be the thin wall 25 amp.
There was no red for the thin wall wire rated at 25 amps.
British Wiring have Red in 44/0.30 thinwall and 28/0.30 'normal'-insulated, the latter's rated for 17.5A; in practice, between the thinner insulation on the thicker conductor and vice versa, you'll find both wire types about the same overall thickness. Fwiw, even though 44/0.30 thinwall's 33A rating is probably overkill even on a Gold Wing with all the accessories, I've used it sometimes. :)

for each of the red earth wires coming off of the components in the nacelle such as the pilot light. Should they be the 25 amp as well or will the 14 strand do.
14-strand is ample for wires between individual components and the snap connectors - standard metric 14-strand's rated for 8.75A, if the standard pilot bulb is 6? Watts, that's 0.5A (the relationship is Watts = Amps x Volts aka P=IE).

Another digression - have you given any thought to the lighting you'd like - and/or is required by your state laws - when you're actually riding the bike? E.g. while I appreciate you might not want the 100-Watt main-beam headlamps I like, :whistle or car-style main-beam-on-with-dip, do you want something brighter than a standard '57 pilot lamp at the front, especially if your state laws includes lights-on-in-daylight? With brighter and better-focussed modern headlamps, I found it better to use a 20W quartz-halogen pilot bulb when I more wanted the bike to be seen by other road users without dazzling them, rather than using the headlamp - say around town under streetlamps.

However, other particularly twin owners have reported that q-h pilot bulbs haven't lasted long for them and, thanks mainly to "rambo" here, Eagle Eye LED are well-known - e.g. the linked type are also available in 10W and 20W, all fit through a standard pilot bulb hole in a headlamp reflector, secure in place with the locknut, have separate Red and Black wires (Red for connecting to the "ground wires" network you're adding, Black for connecting to the PRS8's standard pilot bulb terminal) ... and give useful light. :thumb

At the rear, with the standard small rear lamp, I'm not a fan of the tail-lamp filament being on in daylight - ime reduces an already-feeble contrast between tail and stop when the average driver has so many distractions. :rolleyes: LED 'bulbs' or bulb-replacement boards with LED arrays make a better contrast between tail and stop but (here in GB we don't have any lights-on-in-daylight law), if I must ride with a front lamp illuminated to be seen, I still prefer the tail lamp to be off unless the conditions (darkness, mist/fog, etc.) warrant me switching it on.

Hth.

Regards,
 
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