Triumph Rat Motorcycle Forums banner

1 - 20 of 32 Posts

·
Registered
Joined
·
58 Posts
Discussion Starter #1
Somehow I've managed to get power to the coils/points through the headlight toggle switch without the key/ignition being switched on. The oil pressure (red light) pilot light(first position) and headlight (second position) all function without the ignition being switched on.
Spark at the points would indicate the I've somehow bypassed the ignition switch.
The ignition switch still functions as well.
Any thoughts/help greatly appreciated.

Sent from my SM-G973U using Tapatalk
 

·
Moderator
Joined
·
6,869 Posts
Hi Rod,

Is your bike a T140V or a T140E? Have you changed the Lighting switch ("headlight toggle switch"), or disconnected and reconnected wires recently? Or what other work have you done on the bike recently?

Coils are supplied through the White/Yellow wires. However, that's only from the handlebar kill switch; the switch is supplied by a White wire, as is the oil pressure warning lamp and switch. Normally, the ignition switch has to be 'on' for White wires to be energised. As both coils and o.p. warning lamp are working even when the ignition switch is 'off', that suggests you've connected a White wire to the Lighting switch which you shouldn't have done. Also if the ignition switch is off, does pulling the front brake lever or pressing the rear brake lever two cause the brake lamp to light? If they do, that'd confirm a wrongly-connected White wire because White wires supply the two brake lamp switches.

Hth.

Regards,
 

·
Registered
Joined
·
1,182 Posts
Hi Rod,
I looked in your profile, are you talking about the 78 T140 you list, and the picture of the blue bike. These do not seem to match. 78 was a strange year for model change in the USA. In 77 there was the T140V, in 79 there was the T140E . But in 78 there was sent to the USA only a hybrid of the two, confusingly still called the T140E.
The 79 T140E (proper) is negative earth, has the ignition key in the middle of the clocks and black switches and electronic ignition.
The 78 T140E (hybrid) is positive earth, has the ignition switch on the left headlamp ear and points ignition.

The photo you have posted looks to me as if it is a T140E (proper).
I have both and it is important that the correct one is identified when it comes to wiring, additionally for the ignition do you know if the bike was originally a California bike, as this runs lights on all of the time so the ignition wiring differs from standard.
Your bike in Blue (Looking beautiful). If you can post the first part of the frame/engine number, just the T140 then the 3 letters then it might help identify the bike.
721345


My USA hybrid is the white one, repatriated from Pennsylvania. Note the silver colour switches and no central ignition switch
721346


regards
Peg.
 

·
Registered
Joined
·
58 Posts
Discussion Starter #4
Yes, I have replaced the lighting switch. And yes, I've reconnected the wires to the switch. Probably misconnecting something. My bike, purchased in June 79 is in fact a 78' T140E (Positive Earth)
With Amal MKII Carbs. (BX5044)
I will take into account your info on the wires and repost my findings. Thank you for for help.

Sent from my SM-G973U using Tapatalk
 

·
Moderator
Joined
·
6,869 Posts
Hi Rod,

I have replaced the lighting switch.
Ta-daa ... :)

The '78 T140V and T140E have two completely-different Lighting toggle switches, the T140E's so it could be wired for lights-on-with-ignition to comply with the 1978 FMVSS.

Either switch will have a 5-figure number either moulded on its plastic casing or stamped by the lever:-

. The T140V's Lighting switch is 34419. This is the one shown in all ('71-)'78 (650 and) 750 twin wiring diagrams.

. The '78 T140E's parts book lists 31788 for the Lighting switch (although 35710 works exactly the same). Afaik, there isn't any wiring diagram for the 31788/35710 Lighting switch. :( Either can be wired one of two ways:-

.. for lights-on-with-ignition, Brown/White wire from ignition switch to Lighting switch terminal 1;

.. for lights switched separately, Brown/White wire from ignition switch to Lighting switch terminal 4;

.. for both, Brown/Green wires (tail-lamp, pilot lamp, speedo. 'n' tacho. lamps) to Lighting switch terminal 7; Blue wire (headlamp dipswitch) to Lighting switch terminal 8;

.. the wire colour you don't connect to it is White. ;)

Toggle switches 31788 and 35710 should be easily-available, they were used interchangeably '68-'70 on all models and '71-74 on the T100.

Ignition switch connections if using a 31788 or 35710 Lighting switch
The terminals side of the ignition switch has either three or four male spade terminals in a line: if three, two are visibly connected together; if four, they're visibly connected together in two pairs:-

. If the Brown/White wire is connected to Lighting switch terminal 1, it must not be connected to an ignition switch terminal visibly connected to the Brown/Blue wire (or you won't be able to turn off the lamps ... :));

. If the Brown/White wire is connected to Lighting switch terminal 4:-

.. if the other end of the Brown/White wire is connected to an ignition switch terminal visibly connected to the White wire(s), turning off the ignition switch will also switch off any lamps; (y)

.. otoh, connecting the other end of the Brown/White wire to an ignition switch terminal visibly connected to the Brown/Blue wire allows the lamps to be switched independently of the ignition switch (e.g. if you want the 'parking lights' facility?) but you have to remember to check the lights are switched off at the end of a ride ... :unsure:

Hth.

Regards,
 

·
Moderator
Joined
·
6,869 Posts
Hi Peg,

78 was a strange year for model change in the USA. In 77 there was the T140V, in 79 there was the T140E . But in 78 there was sent to the USA only a hybrid of the two, confusingly still called the T140E.
If I understand past posts (particularly @KADUTZ's) on the subjects correctly:-

. In the '78 model year, the US received both T140V's and the "hybrid" T140E's. The more important changes to the T140E ("E" for "emissions") were the parallel-inlet-port cylinder head, Mk.2 carbs. and revised crankcase and frame spine venting (no more to atmosphere), which the "hybrid" had to comply with stricter 1978 EPA limits.

. Otoh, the '78 T140E's electrical changes were to comply with the 1978 Federal Motor Vehicle Safety Standard, which required lights-on-with-ignition (previously only a requirement in certain states).

. Both the lower emissions limits and the FMVSS only applied to vehicles built on or after 1st January.

Hth.

Regards,
 

·
Registered
Joined
·
58 Posts
Discussion Starter #7
Hi Rod,


Ta-daa ... :)

The '78 T140V and T140E have two completely-different Lighting toggle switches, the T140E's so it could be wired for lights-on-with-ignition to comply with the 1978 FMVSS.

Either switch will have a 5-figure number either moulded on its plastic casing or stamped by the lever:-

. The T140V's Lighting switch is 34419. This is the one shown in all ('71-)'78 (650 and) 750 twin wiring diagrams.

. The '78 T140E's parts book lists 31788 for the Lighting switch (although 35710 works exactly the same). There isn't any wiring diagram for the 31788/35710 Lighting switch. :( Either can be wired one of two ways:-

.. for lights-on-with-ignition, Brown/White wire from ignition switch to Lighting switch terminal 1;

.. for lights switched separately, Brown/White wire from ignition switch to Lighting switch terminal 4;

.. for both, Brown/Green wires (tail-lamp, pilot lamp, speedo. 'n' tacho. lamps) to Lighting switch terminal 7; Blue wire (headlamp dipswitch) to Lighting switch terminal 8;

.. the wire colour you don't connect to it is White. ;)

Toggle switches 31788 and 35710 should be easily-available, they were used interchangeably '68-'70 on all models and '71-74 on the T100.

Ignition switch connections if using a 31788 or 35710 Lighting switch
The terminals side of the ignition switch has either three or four male spade terminals: if three, two are visibly connected together; if four, they're visibly connected together in two pairs:-

. If the Brown/White wire is connected to Lighting switch terminal 1, it must not be connected to an ignition switch terminal visibly connected to the Brown/Blue wire (or you won't be able to turn off the lamps ... :));

. If the Brown/White wire is connected to Lighting switch terminal 4:-

.. if the other end of the Brown/White wire is connected to an ignition switch terminal visibly connected to the White wire(s), turning off the ignition switch will also switch off any lamps; (y)

.. otoh, connecting the other end of the Brown/White wire to an ignition switch terminal visibly connected to the Brown/Blue wire allows the lamps to be switched independently of the ignition switch (e.g. if you want the 'parking lights' facility?) but you have to remember to check the lights are switched off at the end of a ride ... :unsure:

Hth.

Regards,
your post to my question is greatly
Hi Rod,


Ta-daa ... :)

The '78 T140V and T140E have two completely-different Lighting toggle switches, the T140E's so it could be wired for lights-on-with-ignition to comply with the 1978 FMVSS.

Either switch will have a 5-figure number either moulded on its plastic casing or stamped by the lever:-

. The T140V's Lighting switch is 34419. This is the one shown in all ('71-)'78 (650 and) 750 twin wiring diagrams.

. The '78 T140E's parts book lists 31788 for the Lighting switch (although 35710 works exactly the same). There isn't any wiring diagram for the 31788/35710 Lighting switch. :( Either can be wired one of two ways:-

.. for lights-on-with-ignition, Brown/White wire from ignition switch to Lighting switch terminal 1;

.. for lights switched separately, Brown/White wire from ignition switch to Lighting switch terminal 4;

.. for both, Brown/Green wires (tail-lamp, pilot lamp, speedo. 'n' tacho. lamps) to Lighting switch terminal 7; Blue wire (headlamp dipswitch) to Lighting switch terminal 8;

.. the wire colour you don't connect to it is White. ;)

Toggle switches 31788 and 35710 should be easily-available, they were used interchangeably '68-'70 on all models and '71-74 on the T100.

Ignition switch connections if using a 31788 or 35710 Lighting switch
The terminals side of the ignition switch has either three or four male spade terminals: if three, two are visibly connected together; if four, they're visibly connected together in two pairs:-

. If the Brown/White wire is connected to Lighting switch terminal 1, it must not be connected to an ignition switch terminal visibly connected to the Brown/Blue wire (or you won't be able to turn off the lamps ... :));

. If the Brown/White wire is connected to Lighting switch terminal 4:-

.. if the other end of the Brown/White wire is connected to an ignition switch terminal visibly connected to the White wire(s), turning off the ignition switch will also switch off any lamps; (y)

.. otoh, connecting the other end of the Brown/White wire to an ignition switch terminal visibly connected to the Brown/Blue wire allows the lamps to be switched independently of the ignition switch (e.g. if you want the 'parking lights' facility?) but you have to remember to check the lights are switched off at the end of a ride ... :unsure:

Hth.

Regards,
Your post to my question is greatly appreciated and most helpful. I look forward to confirming the switch numbers and visibly confirming the wiring connections . I will repost with the results.THANK YOU!!!!!
 

·
Registered
Joined
·
1,182 Posts
Hi
I found this on Hermits brilliant Triumph pages to distinguish between the two switches 31788 and 35710


  • SMOKE, SMOLDER>, and IGNITE> (earlier models),
    or
  • DIM, FLICKER>, and OFF> (later models)

  • Sorry, couldn’t resist reposting it.
 

·
Registered
Joined
·
1,182 Posts
Hi Rod,
This is interesting to me as I did not think your bike existed.
My 78 T140E has:
the early ‘V’ clocks type clocks mounted on the fork legs
, droopy arse rear mudguard,
round grab rail,
single position ignition switch mounted in the left headlamp ear, and a toggle lighting switch mounted on the headlamp bowl,
Siver bar switches-with pressed steel levers
Square side seat
12V electrics and originally points.
it’s basically a T140V with a modified Triumph Tiger head and mk2 amal Carbs + modified breather.

My Black 1980 T140E behind it in the photo has:
Grab rail with rack
Originally drop side seat
Raised rear mudguard
Modified Tiger head , mk 2 carbs
Negative earth electronic ignition
Black switches with cast alloy levers
Importantly
The clocks are in a binnacle mounted on the top yoke, with the combined lighting/ignition switch mounted in between them.
There is No toggle switch for the lights in the headlamp.

The ignition switch is 4 position switch, sidelights , off, ignition/accessories and ignition/accessories + headlamp.

The photo from your Blue T140E looks exactly like this, but you have a toggle light switch, points and positive earth.
I can see the clock binnacles and the ignition key between them in your photo.

How many positions does the ignition switch have-two (on/off) or 4 (Sl, off, on, on+lights)?

I have never seen a hybrid bike like this before, It seems to before-a kind of downgraded later bike, very strange and incredibly rare.

Regards
Peg.
 

·
Registered
Joined
·
5,351 Posts
Good Evening
Haven't been posting much lately. Been working from home this is my third week of long hours.

The Blue/Silver bike shown in the thread and on the OP Profile Page is a 1979 T140E. It will have a VIN greater than HA 11001.
To be a 78 T140E the VIN would be about AX 04000 or greater/later.

I suspect that the Blue bike is not the one that Conrodt is working on as in earlier post it was mentioned his fuel tank was bad and was looking for a UK Seat to go with a UK tank.

Regarding the 1978 T140V vs T140E cosmetically they looked the same. One difference was the V had a black taillight housing while the E had polished housing. Also the airbox covers and airbbox assembly were different due to the new head and carbs.

1978 T,140E was the only 1978 model imported after 1/01/1978. (Granted any Triumph produced prior to that date could be imported)
T140V and TR7V were still produced for home & general export. I would be interested in knowing the first part of the VIN of the bike in question

K
 

·
Moderator
Joined
·
6,869 Posts
Hi K,

interested in knowing the first part of the VIN of the bike in question
Afaict from the context of these two posts:-

If you can post the first part of the frame/engine number, just the T140 then the 3 letters then it might help identify the bike.
My bike, purchased in June 79 is in fact a 78' T140E (Positive Earth)
With Amal MKII Carbs. (BX5044)
... "BX5044" is the first part of Rod's bike's VIN?

Fwiw, I've an idea how Rod's bike could appear to be a '79 T140E but be a '78 underneath (think T160) but, rather than speculate possibly incorrectly and confuse the issue further, hopefully Rod will add some more pictures/confirm the details?

Regards,
 

·
Registered
Joined
·
58 Posts
Discussion Starter #12
my bike is , in fact a 78' 1/2 with Amal MKII's. Smith's instruments and key in left fork ear. Blue and Silver, not blue and white . Serial # T140E BX5044. Purchased in June of 1979. I'am the original and sole owner of this bike since new.
Regards.
721507
 

·
Registered
Joined
·
58 Posts
Discussion Starter #13
I do NOT have a brown/WHITE wire,...mine is brown/BLUE. It is connected to the 3-4 terminal of the switch # 31788 "lights -switched separately".???
Double Brown/Green to terminal #7 and Blue to terminal # 8
I have disconnected the White wire i had connected to the #1 terminal.
What does it connect to. if anything ?
My ignition switch consists of a Double white and a Double Brown/Green.
the cloth wound wiring harness was purchased "NEW" several years ago and is in good condition.
My concern is of course, that the ignition could be switched on by the headlamp toggle switch without a key.:oops:
 

·
Registered
Joined
·
1,182 Posts
Hi Rod
Sorry for the delay, I had do a covid lockdown sneakout to the garrage.

This is how my 78 lighting switch is wired

Brown/White (ig sw) always live side = 3
Brown/Green (tail lamp + pilot lamp) = 4
Blue (dip switch) = 8
white (stop light/ig switch) switched side =7

a little different from yours.

regards
Peg
 

·
Moderator
Joined
·
6,869 Posts
Hi Peg,

my 78 lighting switch is wired
Brown/White (ig sw) always live side = 3
Brown/Green (tail lamp + pilot lamp) = 4
Blue (dip switch) = 8
white (stop light/ig switch) switched side =7
Mmmm ... but, even if you're talking about a '78 T140E, were you to take the switch out of the headlamp shell and inspect it closely, you'll (99% certain) find it numbered "34419"?

Otoh, Rod posted:-

switch # 31788
Lighting switch
34419. This is the one shown in all ('71-)'78 (650 and) 750 twin wiring diagrams.

The '78 T140E's parts book lists 31788 for the Lighting switch
Afaik, there isn't any wiring diagram for the 31788
Hth.

Regards,
 

·
Moderator
Joined
·
6,869 Posts
Hi Rod,

the cloth wound wiring harness was purchased "NEW" several years ago
So not an original harness, which is what I based my previous advice on. Given the other differences you've mentioned, an educated guess says it's Wassell "Genuine :LOL: Lucas" ...

ignition switch consists of a Double white and a Double Brown/Green.
Are you sure the tracer's definitely Green and not a shade of Blue? Brown/Blue was the 'original Lucas' colour code for the wire attached to the battery "not-ground" terminal since some time in the 1950's; any bike not fitted with an Ammeter, Brown/Blue continued to the ignition switch.

'Original Lucas' did not use the same wire colour/s for entirely-different connections. Specifically Brown/Green was always the 'original Lucas' colour code for wires to pilot bulb and rear bulb tail filament - as you've noted, there are two Brown/Green wires attached to Lighting switch terminal #7; if you wish to be sure, use an Ohmmeter or the Ohms function of a multi-meter to test continuity between Lighting switch terminal #7 and those two bulbs.

Otoh, if you test continuity from the ignition switch, you'll likely find one Brown/whatever wire goes to the rectifier and battery -ve, the other Brown/whatever wire goes to the Zener.

do NOT have a brown/WHITE wire,...mine is brown/BLUE.
connected to the 3-4 terminal of the switch # 31788
Original '78 T140E-specific harness didn't have either Brown/White or Brown/Blue from ignition switch to Lighting switch; these are Lucas colour codes specifically for unswitched connection from/to the battery ('78 T140V has Brown/White).

At the Lighting switch, you should connect the Brown/Blue wire from the ignition switch to terminal #4 specifically (not #3).

"lights -switched separately"
This specifically depends on the ignition switch connection of the Lighting switch Brown/Blue wire in your bike's harness. As in my previous post, the ignition switch has either three or four male spade terminals:-

. if three, you can see two terminals are connected together and one isn't;

. if four, you can see they're connected together in two pairs;

. risking stating the obvious, terminals not connected together on the outside of the switch, are connected together inside the switch just when the switch is 'on'.

ignition switch consists of a Double white and a Double Brown/Green.
White is the Lucas colour code for wires switched by the ignition switch. Otoh, as I've written above, one of the "Double Brown/whatever" wires is unswitched from battery -ve.

So, with "Double white" on one terminal and "Double Brown/whatever" on another terminal not visibly-connected to the White wires' terminal, the White wires are energised only when the switch is 'on' (or the switch is faulty).

So, if you connect the Lighting switch (Brown/Blue?) wire to the ignition switch terminal visibly-connected to the White wires' terminal, the lights will be switched on and off with the ignition. (y)

disconnected the White wire i had connected to the #1 terminal.
Double Brown/Green to terminal #7
The reason Meriden used a 31788 (or 35710) Lighting Switch on the '78 T140E is specifically within those switches terminals/positions #1, #3, #5 and #7 are connected together internally.

So, on an original '78 T140E harness, if a White wire switched by the ignition switch was then connected to Lighting switch terminal #1, and terminal #7 has the Brown/Green wires specifically to pilot bulb and tail filament, those two bulbs would be illuminated all the time the ignition is switched on, to comply with the 1978 FMVSS. (y)

Blue to terminal # 8
Blue supplies the headlamp dipswitch on the handlebars. One Lighting switch position connects terminal #7 to terminal #8. So the headlamp will be on in one Lighting switch position and off in the other two.

My concern is
ignition could be switched on by the headlamp toggle switch without a key.
Not if you carefully read and follow all my advice. ;)

Hth.

Regards,
 

·
Registered
Joined
·
5,351 Posts
Well below is a Post I started Friday morning but never got submitted. Right now running on less than empty. With that said I have a question for Rod. On your original harness were the connections the old bullet style or the modern quick connect style that are held together with a metal clip. Same question for the replacement harness. Also which switch is in the headlamp presently an is the diode still connected in the headlight? The diode assembly will consist of two white leads a a small black diode (working from memory on the diode color.

K

Hi K,


Afaict from the context of these two posts:-



... "BX5044" is the first part of Rod's bike's VIN?

Fwiw, I've an idea how Rod's bike could appear to be a '79 T140E but be a '78 underneath (think T160) but, rather than speculate possibly incorrectly and confuse the issue further, hopefully Rod will add some more pictures/confirm the details?

Regards,
Good morning Stuart ?
I have been reviewing old posts on this machine and Rod has stated multiple times the bike is a 78 T140E . If the number stated (BX5044) is the VIN it would really be BX 05044 T140E. If that is the case that would be a good VIN for a machine built during February 1978 I have seen machines BX 045XX & BX 05051

Again regarding the picture of the Blue/Silver T140E that is not the bike in question in this To convert a 78 T140E to look like the pictured bike would cost a large amount of money.

I see Rod has done a Post confirming the VIN..

K
 

·
Registered
Joined
·
58 Posts
Discussion Starter #18
Hi Peg,


Mmmm ... but, even if you're talking about a '78 T140E, were you to take the switch out of the headlamp shell and inspect it closely, you'll (99% certain) find it numbered "34419"?

Otoh, Rod posted:-




Hth.

Regards,
My Headlight switch has been replaced with a 31788, as the original finally failed.
 

·
Registered
Joined
·
58 Posts
Discussion Starter #19
Well below is a Post I started Friday morning but never got submitted. Right now running on less than empty. With that said I have a question for Rod. On your original harness were the connections the old bullet style or the modern quick connect style that are held together with a metal clip. Same question for the replacement harness. Also which switch is in the headlamp presently an is the diode still connected in the headlight? The diode assembly will consist of two white leads a a small black diode (working from memory on the diode color.

K



Good morning Stuart ?
I have been reviewing old posts on this machine and Rod has stated multiple times the bike is a 78 T140E . If the number stated (BX5044) is the VIN it would really be BX 05044 T140E. If that is the case that would be a good VIN for a machine built during February 1978 I have seen machines BX 045XX & BX 05051

Again regarding the picture of the Blue/Silver T140E that is not the bike in question in this To convert a 78 T140E to look like the pictured bike would cost a large amount of money.

I see Rod has done a Post confirming the VIN..

K
As i recall the ORIGINAL harness had hard white plastic (stock) connectors . It now has a cloth wound replacement harness and a replacement 31788 lighting switch .
The original may have been 34419 as listed in the original 78' parts book i have used for years.
The V.I.N. is , as you've stated T140E BX05044 ..... a 78' model.
The Ignition switch (four termina) also a replacement, has two White ( DOUBLE WHITE) and two Brown/Green (DOUBLE BROWN AND GREEN) wires connected to it.
 

·
Registered
Joined
·
58 Posts
Discussion Starter #20
As i recall the ORIGINAL harness had hard white plastic (stock) connectors . It now has a cloth wound replacement harness and a replacement 31788 lighting switch .
The original may have been 34419 as listed in the original 78' parts book i have used for years.
The V.I.N. is , as you've stated T140E BX05044 ..... a 78' model.
The Ignition switch (four termina) also a replacement, has two White ( DOUBLE WHITE) and two Brown/Green (DOUBLE BROWN AND GREEN) wires connected to it.
CORRECTION.....!!! I've made a mistake ,......My Ignition Switch consists of a Double White and a Double BROWN and BLUE,...NOT BLUE AND GREEN as stated in a previous post, my apologies for any confusion i've created.:cautious:
 
1 - 20 of 32 Posts
Top