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Discussion Starter #1 (Edited)
Evening all,

Finally, I have some space to swing a cat in my workshop, so it's Winter Bonnie Resto Time and along with many things, I need to buy a loom. OK, before anyone sarcastically points me at the search function ;-) I know this subject has been talked about in the past, and I have been searching / reading, but I am looking for an updated viewpoint on what is the best loom available today please. I don't want to make my own (I considered it but want to focus my time on the mechanics and paint), so ideally I want to buy a loom from a UK supplier (not necessarily a UK manufacturer) but not a "Genuine Lucas" loom as are I hear they are nowhere near as good quality as they used to be.

So, a standard T140E Loom for stock components, with the exception of a Boyer ignition system (can I use the Rita wires to connect the Boyer pickup and box?) and a higher-power 3-phase alternator and Podtronics (I presume I will have to create the wiring for this but will the standard loom take 15A?). I believe the '79 T140E could go vinyl or cloth wrapped (I prefer the latter). The L P Williams looms have been recommended to me by a friend who rebuilt his TR7, T150 and T160, all with L P Williams looms, but annoyingly; cloth-wrapped is not in stock.

Any advice please?
Cheers,
Ian
 

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Hi Ian,

Winter Bonnie Resto Time
best loom available today
Ime, diy.

standard T140E Loom
will the standard loom take 15A?
Standard '79, no.

'71-on, probably at the behest of BSA's production accountants, Lucas reduced the size of the wires common to most or all circuits - Brown/Blue. White from the ignition switch and Red back to battery +ve - from 28-strand to 14-strand (the same size as all the other wires in looms). At the time, Lucas rated these wires for 15A and 7.5A respectively; between a safety factor and the standard alternator was rated for 10.5A, Triumphs and BSA's just about managed with all-14-strand wire. Although Triumph then survived in BSA ownership for less than two years, subsequent owners (NVT and the Co-op) never asked Lucas to reverse the '71 changes. :(

The 'best' off-the-shelf looms I know of are Autosparks, although afaik he doesn't sell 'em direct to the public; certainly TMS retail 'em.

Reason I put "best" in inverted commas is Autosparks supplies pretty-much exact copies of original Lucas looms, so a new Autosparks loom for a '79 T140E will be made entirely of 14-strand wire, albeit modern metric which is rated for a whopping 8.75A ... Lucas attached multiple (14-strand) Black wires to battery -ve and fitted two 14-strand White wires up to ignition switch terminal 2, but the Brown/Blue from ignition switch terminal 1 to battery +ve is still a single 14-strand wire ... :(

L.P. Williams don't retail Autosparks looms; as your friend was happy with them, maybe take a look at the aforementioned 'common' wires to see if they're thicker?

Otherwise, the only Co-op twins retailed to Joe Public fitted with high-output alternators as standard were the ones with electric-start; if you must have an off-the-shelf loom, maybe enquire if these had thicker 'common' wires? The only extra wiring you're likely to find in this loom is a White/Red wire intended to connect between one in the right-hand handlebar switch cluster and wherever the starter relay was located, where you'll also find the ends of three other wires.

Another thing to bear in mind if you choose an off-the-shelf loom is it'll likely have the solitary fuse attached to the 'wrong' battery terminal for full protection? :(

can I use the Rita wires to connect the Boyer pickup and box?
It's wiser and neater to use the 3-pin plug to connect the "Transistor Box" to the loom, rather than hacking the loom about to replicate Bransden's shonky connections.

However, the two wires between Box and Stator ... mmm ... Problem is Lucas used White/Orange and White/Purple, fine if you can always remember the connections to Bransden's Black/White and Black/Yellow at both ends?

Fwiw, when fixing looms that've been hacked about to fit B-B e.i., I change the 3-pin plug for a 5-pin that uses the same terminal types, then using the two additional terminals for the two wires to the Stator, I connect the Stator Black/White and Black/Yellow to the loom White/Orange and White/Purple with a 2-pin plug that can be connected only one way.

Podtronics (I presume I will have to create the wiring for this
Another reason to consider the later loom is the bikes didn't have your bike's standard Zener. Then I hope you'll connect the reg./rec. DC directly to the battery terminals, rather than faffing about with the Brown/Blue wire's original rectifier connection?

'79 T140E could go vinyl or cloth wrapped
Depends how 'original' you want to end up? I've never seen original looms cloth-wrapped on T140E's; ime, Lucas changed to taping years before.

Hth.

Regards,
 

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My t140 was made in November 78 as a 79 and was 4 years old when I bought it.
Plastic wrapped, almost certainly original loom
 

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Discussion Starter #4 (Edited)
Thanks Chaps. Plastic it is!

Stuart: TMS have replied to me and said that the standard Autosparks T140E loom will take 15A but if what you say about the wires only being able to cary 8.75A, I don't see how this can be the case.

According to THIS DIAGRAM, in the standard setup the current from the alternator goes 3 ways from the rectifier:

1. To the battery (if it is below ~13V).
2. To the Zener (for surplus beyond the preceding 2 uses above).
3. To the ignition switch (possibly via the Zener) onto the electrical components (such as lights and ignition).

The brown/blue from the battery will at worst be required to carry all the current for ignition and lighting. Even then, this will only apply in a maximum discharging scenario, i.e having all the electrics on where the engine is not running (or the charging system fails whilst riding), probably drawing about 7A, and which is an unlikely situation to persist for long. So, the cable will be fine.

For the other direction, I am told that even if the battery is completely flat and taking full charging current, its internal resistance will not allow it to accept the full 14.5A. The wire between rectifier and battery will never see that level of charging or discharging current. Keep in mind that the max voltage that can be applied is around 15V. So, the rectifier to battery should be fine and let's not forget that I am planning to fit the Podtronics which connects directly to the battery.

In the diagram, it seems that the Blue/Brown (NU) wire to the ignition switch, comes from the Zener connection. If this is the case, then it is the Blue/Brown from Regulator to Zener that is most at risk. The worst condition would be with a fully charged battery drawing negligible current, so with a high-output alternator at full chat, all of the available current (to the electrical system and/or the Zener, will be delivered via the wire between the rectifier (or battery in the Podtronics installed scenario) and Zener. If your comment about the maximum current capacity of 14 strand wire being only 8.75A is correct, this is the potentially risky scenario as this wire will get rather hot with the bike electics and Zener drawing current through it.

If the diagram is not accurate as to where the Blue/Brown wires are connected, for example if there are separate NU wires from regulator to the Ignition and Zener then the risk would be somewhat mitigated by having the lights on, as the electrical components would draw say 7A along 1 wire, leaving about the same to the Zener down another and allowing for a trickle charge to the battery along the third. this is better, but not ideal and this paragraph assumes the lights are on and there are individual wires to the Zener and Ignition, whereas the diagram seems to suggest everything (apart from battery charge) goes via that wire to the Zener...

Looking at the podtronics 3-Phase WIRING DIAGRAM it appears I don't need to worry about the Zener. All I need is the 3-Phase, high-output alternator and the Podtronics box connected to the battery. Please excuse my lack of knowledge of the Podtronics but is this the case? Does the Podtronics box take care of both the rectifier and Zener functions? If so, I can use the Green/White, Green/Black and Green/Yellow loom wires to connect the high-power alternator (at around 5A each max), then site the Podtronics near where the original rectifier currently lives and connect this to the other end of the three loom alternator wires, then simply connect the Podtronics +ve and -ve wires directly to the battery (fused of course). System power then going direct to the ignition switch from the battery. If the Zener is still required (and I am not sure it is) then I will get a length of 28 strand or higher Blue/Brown wire for the run from battery to the Zener (this is essentially the path that replaces the original daisy chain Rectifier to Zener). Then the new loom's 14 strand NU from the Zener to the ignition should be more than man enough to supply the bike electrical system.

Does that all make sense?
Ian
 

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Hi Ian,

TMS
said that the standard Autosparks T140E loom will take 15A but if what you say about the wires only being able to cary 8.75A,
Why not just ask Autosparks? :)

The original non-electric start '79-on twin looms I've dealt with had all-14-strand wire.

Some time ago, to help someone out in one of the forums, I rang Autosparks to ask if they would make a particular Triumph loom with several changes, one change would've been the Brown/Blue in 28/0.30 thinwall. The person at Autosparks said they did not make changes when building Triumph looms, they copied what Lucas did. As I've been dealing with Autosparks for over thirty years and know certain people there can be relied upon either to give good advice or pass on the question to someone who can, I didn't have any reason to doubt the advice.

Looking at the podtronics 3-Phase WIRING DIAGRAM it appears I don't need to worry about the Zener.
Correct. The Pod is a reg./rec. (regulator/rectifier) so it replaces both Zener (original regulator) and original rectifier

I can use the Green/White, Green/Black and Green/Yellow loom wires to connect the high-power alternator
You might not need to; you could well find the new alternator stator wires can be connected directly to the Pod Yellow wires. (y)

connect the Podtronics +ve and -ve wires directly to the battery (fused of course).
(y)

the new loom's 14 strand NU
should be more than man enough to supply the bike electrical system.
Bearing in mind of course it's the Black wire(s) attached to battery -ve that are DC supply and the NU attached to battery +ve is the DC return ... ;)

Also bear in mind the Pod (any reg./rec.) also regulates according to DC load. So, even if the engine was @ 5,000 rpm and the alternator was generating 14.5A or more, if you were riding lights-off, if the battery was charged, the only DC load would be the ~3.5A of the ignition system ... which is all the Pod would rectify, the remaining ~11A would be turned into heat by the Pod without being rectified. (y)

Otoh, even if the battery is badly-discharged, if the Pod's DC wires are attached directly to the corresponding battery terminals, none of the loom wires will carry any battery-charging Amps.

If a new Autosparks loom does have 14/0.30 Black, White and Brown/Blue wires, if the maximum DC current never exceeds 8.75A plus whatever safety margin, it's your bike; if you're happy ... Personally, the cost of a few metres of Brown/Blue, White and Red (on my Triumphs) 28/0.30 thinwall means I never have to worry how many Amps might or might not be going through 'em at any given time. :)

In the diagram, it seems that the Blue/Brown (NU) wire to the ignition switch, comes from the Zener connection. If this is the case, then it is the Blue/Brown from Regulator to Zener that is most at risk.
The point is academic:-

. Your bike won't have a Zener as you're fitting a Pod and connecting its DC wires directly to the battery terminals.

. Originally, neither original Lucas high-output alternator (RM23 single-phase or RM24 3-phase) was fitted with a single Zener - Lucas reckoned a single Zener was only good for about 12A~12.5A. So the RM23 was fitted with an unmatched Zener attached to each alternator-rectifier wire; similarly, each RM24 alternator-rectifier wire was connected to a Zener in a strip of three; after the high-output RM24 became an option even on non-electric-start twins, they all got the 3-Zener strip irrespective of the actual 3-phase fitted.

Hth.

Regards,
 

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Discussion Starter #6
Thanks Stuart, appreciated.

Why not just ask Autosparks? :)
I did, in fact I asked both TMS and Autosparks. Only TMS bothered to reply...

The Pod is a reg./rec. (regulator/rectifier) so it replaces both Zener (original regulator) and original rectifier
Great!

"I can use the Green/White, Green/Black and Green/Yellow loom wires to connect the high-power alternator"
You might not need to; you could well find the new alternator stator wires can be connected directly to the Pod Yellow wires. (y)
I know, but I quite like the idea of limiting the wiring to the new loom, with no extra wires. E.G. if I do replace supply and return wires with heavier gauge of the same colour, I will open the loom, replace and rewrap.

Also bear in mind the Pod (any reg./rec.) also regulates according to DC load. So, even if the engine was @ 5,000 rpm and the alternator was generating 14.5A or more, if you were riding lights-off, if the battery was charged, the only DC load would be the ~3.5A of the ignition system ... which is all the Pod would rectify, the remaining ~11A would be turned into heat by the Pod without being rectified.
Understood. I assume that when hooked up to a 180W alternator, with a fully charged battery and no significant load, the Podtronics has to lose quite a lot of heat. If so, where is the best place to site it? I was hoping to keep it out of site. Would it get enough air (and actually fit) where the existing T140E rectifier lives? (This would also allow me to use the loom to connect the alternator and rectifier.

One last question (for now): What is the best, money no object, high-output stator out there? I saw Lunmad's review of the new Wassel Lucas that had failed and I know you slate Wassel products all the time for being poor quality, but what is the best alternative to the RM24? Sparks do one which I read is just an RM24 copy but is it better than a green box? Are their any others to consider? I want an electrical system that will be hassle-free and reliable for many years...

Cheers,
Ian
 

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Hi Ian,

TMS have replied to me and said that the standard Autosparks T140E loom will take 15A but if what you say about the wires only being able to cary 8.75A,
I asked both TMS and Autosparks. Only TMS bothered to reply...
Mmmm ... helpful ... Just a thought but, if you e-mailed, possibly only one person (the boss?) at Autosparks answers e-mails with technical questions? Fwiw, I always 'phone.


I can use the Green/White, Green/Black and Green/Yellow loom wires to connect the high-power alternator

You might not need to; you could well find the new alternator stator wires can be connected directly to the Pod Yellow wires. (y)
I quite like the idea of limiting the wiring to the new loom, with no extra wires. E.G. if I do replace supply and return wires with heavier gauge of the same colour, I will open the loom, replace and rewrap.
This is confused:-

. "supply and return wires" are DC Black and Brown/Blue respectively;

. otoh, in an original loom, the White/Green, Green/Black and Green/Yellow wires connected the corresponding wires from the stator to the AC male spade terminals on the rectifier.

. If the new loom copies an original loom, the White/Green, Green/Black and Green/Yellow will have bullet terminals at one end - to connect to the stator wires - and female spade terminals at the other end - to connect to a rectifier.

. With the new loom, you might have to fit the Pod AC wires with male spade terminals to connect to the female spade terminals, and connect the stator wires to the corresponding wires in the new loom; however, that's two connections in each AC wire. Otoh, if the Pod AC wires will reach the stator wires directly, why wouldn't you connect them together directly, so there is only one connection in each AC wire?

hooked up to a 180W alternator, with a fully charged battery and no significant load, the Podtronics has to lose quite a lot of heat.
Afaik, the Pod itself doesn't have to lose all the heat. If I understand "NickL" on BritBike correctly, because the Pod is a shunt reg., "shunting" simply connects stator AC wires together, reducing the current generated and some of the heat is also then lost from stator coils and connecting wires.

where is the best place to site it?
If my understanding's correct. the Pod simply has to be sited where there's some airflow, which there'll be even behind sidepanels, there isn't any need for it to be fully-exposed.

you slate Wassel products all the time for being poor quality,
... from far too much first-hand experience ... 🤬

best, money no object, high-output stator out there?
Ime and mho, what the trade simply labels the "Made In England" one (the maker used to stamp "LUCAS" on 'em as well but, since Wassell's exclusive deal with the Lucas trademarks owner and Wassell spends most on lawyers to enforce its deal ... :rolleyes:). While it isn't the only retailer that sells 'em, TMS list them on TMS Nottingham

47244ALTERNATOR STATOR 12v 3 PHASE 180w 14.5amp LUCAS£69.00
47244/UKALTERNATOR STATOR 12v 3 PHASE 180w T140 ELECTRIC START 14.5amp UK MADE£75.00
... risking stating the obvious, the cheaper "LUCAS" one is Wassell, "UK MADE" is TMS's abbreviation of "Made In England".

Regrettably, again, ime variable quality. :(

Hth.

Regards,
 
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