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77 T140V wiring question #118024
06/13/07 3:15 pm
06/13/07 3:15 pm
Joined: Oct 2006
Posts: 252
Stow, MA
Pete J 77T140 Offline OP
BritBike Forum member
Pete J 77T140  Offline OP
BritBike Forum member
Joined: Oct 2006
Posts: 252
Stow, MA
Hey,

I have looked at a bunch of wiring diagrams for my bike and I'm confused about a couple of things.

First, the stock headlight switch on my bike is set up as follows:

Pole 1 - no wire
Pole 2 - this pole does not exist
Pole 3/4 - - are combined as a single male spade connector with a Brown/white unswitched power wire attached
Pole 5/6 - - are combined as a single male spade connector with no wire attached.
Pole 7 is a single male spade connector with a Brown/white wire attached (this powers pilot light, instrument lights and tailight)
Pole 8 is a single male spade connector with a Blue yellow wire attached (this powers headlamp hi and low beam and indicator)

Switch in pilot position powers pole 7 but not 8. In full on position switch powers pole 7 and pole 8.

This all works just fine, but no diagram I have seen shows a switch or wires that are set up this way. What's up with that?

_______________________________

My second question has to do with the way that the white "switched" (by the ignition switch) wires are laid out on my diagram.

The diagram shows a white wire passing from the power out side of the ignition switch to pole 7 of the headlight switch and then continuing on to the front brake light switch and then ultimately to the brake light and to ground after the brake light. I would think this wire should be straight from the ignition switch to the front brake light switch. Why would it pass through the headlight switch?

Even getting more beers on board as I stared a hole in a schematic diagram late last night did not help me to solve this one! But at least I enjoyed the beer! 8-)

Cheers,

Pete

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Re: 77 T140V wiring question #118025
06/13/07 4:26 pm
06/13/07 4:26 pm
Joined: Nov 2005
Posts: 7,257
Back on the mainland!
JubeePrince Online content

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JubeePrince  Online Content

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Joined: Nov 2005
Posts: 7,257
Back on the mainland!
Pete -

First let me preface this by saying that my electrical abilities are suspect at best...

I think the following taken from the factory manual illustrates your switch:
[img]http://im1.shutterfly.com/procserv/47b7d832b3127cce859d45a5074c00000025108IcuW7Zu4cm[/img]
where settings for (a) everything off; (b) parking lamp, instrument and tail light; (c) all lights (excluding stop light unless activated).


Not sure about the white wire passing thru the headlamp switch..... do know that there are four wires for the front brake light switch and the kill switch that are connected to the harness in the headlight shell through a plastic four-pin male/female connector.....I believe the white wire (feed) is spliced into the Blue/Yellow wire, which is attached to the headlamp switch.....

There are two schematics in the factory manual.....one has the horn wired to the right hand switch....(pg H21)....my bike has the horn on the left switch along with dip switch and turn signals......front brake switch and kill switch are on the right-hand side.....if this is the case for your bike...use the schematic on page H22......

I'm sure someone with more electrical knowledge than me will chime in and correct my mistakes, but it's a start........Stuart?? Andrew??


HTH,

Steve


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
Re: 77 T140V wiring question #118026
06/13/07 4:40 pm
06/13/07 4:40 pm
Joined: Nov 2004
Posts: 1,694
georgia
T
trumpetloon Offline
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trumpetloon  Offline
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T
Joined: Nov 2004
Posts: 1,694
georgia
FWIW I recently cleaned up the wiring on my '76 T140V. My manual has only the schematic described by Steve where the switch wiring is misplaced.

With the help of my father in law who is an avionics technician, and ahout 6 hours of head scratching and wire tracing we got it done... definitely not to schematic but it all works. Adding confusion was the switch itself... identical looking but switched differently than original. We ended up treating each switch function as an individual, and through process of elimination got it sorted. Frustrating to say the least! Made more sense as we got a couple hours into the process though.


1974 TR5T
Re: 77 T140V wiring question #118027
06/13/07 5:03 pm
06/13/07 5:03 pm
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
RF Whatley Offline
BritBike Forum member
RF Whatley  Offline
BritBike Forum member
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
Pete -
By 1977 (when your bike was new) governments all over the world were trying to make motorcycles safe for the consumer. So all sorts of diabolical schemes were dreamed up by various "safety committees" and enacted into law. And governments being what they are, they all had different views of what was safest for Canadian, German, US , Zambonian, etc. motorcyclist. A lot of these laws had to do with what could, or could not, be going on at a certain ignition key switch position.

Therefore, manufacturers like Triumph were sometimes forced to use different ignition switches for each country in order to sell bikes there. But with small manufacturers, not only were most of these variations not documented in the parts books, but the schematics were not updated beyond what they considered "standard". I feel sure your bike falls into this "documentation free" zone.


A wiring diagram or "schematic" is just that, a graphical representation of the power flow, not a drawing to actually build the wiring harness by. For instance, some older schematics might show the headlamp next to the tail lamp. We all know that isn't their true physical placement, it's simply enough to know during troubleshooting that BRN/GRN supplies power to both lamps at the same time.

And so it is with your WHT wire. It's simply enough to know that when the ignition switch is turned ON, that power coming from the BRN/BLU wire passes through the switch and connects to the WHT wire, which then takes power to both brake lamp switches, the headlamp, the ignition coils and several other items.

More modern schematics have tried to become more closely drawn to the physical reality, but given the number of wires inside the headlamp versus the number inside the tail lamp, this is not always possible on a small piece of paper. So a schematic may or may not be a good physical representation.

bigt


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
Re: 77 T140V wiring question #118028
06/13/07 7:13 pm
06/13/07 7:13 pm
Joined: Oct 2006
Posts: 252
Stow, MA
Pete J 77T140 Offline OP
BritBike Forum member
Pete J 77T140  Offline OP
BritBike Forum member
Joined: Oct 2006
Posts: 252
Stow, MA
Thanks guys,

Hi Jubee -- sounds like your handlebar switches are the same as mine (I remember those silver Jubilees -- very nice bikes -- I got my Bonneville just before the Jubilee's came out and I remember wishing that I had waited a bit and got one of those.) My bike's pretty much all stock with the blue and white tank. Only change is low AMC style bars and a smaller taillight. I am also working on getting Norton peashooter mufflers to work on the bike -- the original ones developed holes.

Is your headlight switch arrangement the same as I have described above?

Thanks for the explanation RF. At least I don't feel like I'm going crazy now!

You say that "It's simply enough to know that when the ignition switch is turned ON, that power coming from the BRN/BLU wire passes through the switch and connects to the WHT wire, which then takes power to both brake lamp switches, the headlamp, the ignition coils and several other items."

I thought that the headlamp was supplied power by the Brown/white feed which is before the ignition switch (this feed is connected to pole 3/4 on my headlamp switch), and that this is why my headlamp works when the ignition is switched off.

Is there are also a white lead supplying power to the headlamp from power that is after the ignition switch?

Pete

Re: 77 T140V wiring question #118029
06/13/07 7:39 pm
06/13/07 7:39 pm
Joined: Nov 2005
Posts: 7,257
Back on the mainland!
JubeePrince Online content

Life member
JubeePrince  Online Content

Life member
Joined: Nov 2005
Posts: 7,257
Back on the mainland!
Quote:
Originally posted by Pete J 77T140:
Is your headlight switch arrangement the same as I have described above?
Yes........
[img]http://im1.shutterfly.com/procserv/47b7d832b3127cce859f341107c000000026108IcuW7Zu4cm[/img]

HTH,

Steve


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
Re: 77 T140V wiring question #118030
06/14/07 12:55 pm
06/14/07 12:55 pm
Joined: Oct 2006
Posts: 252
Stow, MA
Pete J 77T140 Offline OP
BritBike Forum member
Pete J 77T140  Offline OP
BritBike Forum member
Joined: Oct 2006
Posts: 252
Stow, MA
Thanks Steve. It was above and beyond the call for you to take that headlamp apart to photo its guts for me but it helps me a huge amount. Oh and it looks very neat in there - nice work. Mine is a spaghetti bowl of wires right now!

You have the same switch as mine but it is hooked up differently -- I must have switched some wires around somehow.

Cheers,

Pete

Re: 77 T140V wiring question #118031
06/14/07 4:55 pm
06/14/07 4:55 pm
Joined: Nov 2005
Posts: 7,257
Back on the mainland!
JubeePrince Online content

Life member
JubeePrince  Online Content

Life member
Joined: Nov 2005
Posts: 7,257
Back on the mainland!
Pete -

I didn't do it for you! :p

I took photos this spring as I disassembled my original loom to replace with a new one....it look clean, because I moved everything out of the way to take my photos of the switch.....

Not sure of your exact circumstances with your bike, but a digital camera is a great investment to take photos before you start pulling things apart.... bigt

Cheers,

Steve


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
Re: 77 T140V wiring question #118032
06/15/07 12:07 am
06/15/07 12:07 am
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
RF Whatley Offline
BritBike Forum member
RF Whatley  Offline
BritBike Forum member
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
Quote:
Originally posted by Pete J 77T140:
I thought that the headlamp was supplied power by the Brown/white feed which is before the ignition switch (this feed is connected to pole 3/4 on my headlamp switch), and that this is why my headlamp works when the ignition is switched off.
Might be my bad. I was writing from work without books or diagrams, but you got the general picture.

bigt


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
Re: 77 T140V wiring question #118033
06/15/07 12:27 pm
06/15/07 12:27 pm
Joined: Oct 2006
Posts: 252
Stow, MA
Pete J 77T140 Offline OP
BritBike Forum member
Pete J 77T140  Offline OP
BritBike Forum member
Joined: Oct 2006
Posts: 252
Stow, MA
Hey

RF -- that's OK, your "bad" is a lot better than my "good" 8-). I'm going to do some looking around and testing to see if indeed that white wire somehow supplies or supplements power (as the diagram suggests).

Then I'm going to take my wire diagram, blow it up to 11 by 17 inches, and revise it to reflect my bike, which is now a negative ground (did this so so I could run a headlamp flasher) with a Tymp, and a SPG, and probably a few redundant ground wires around as well (My approach on grounding was "when in doubt attach it to the SPG".

This will give me and my next of kin (I'll never sell it!!) a chart to use for this specific bike.

Steve -- great idea about using the camera to document how things were set up before you take them apart.

Cheers,

Pete

Re: 77 T140V wiring question #118034
06/15/07 4:45 pm
06/15/07 4:45 pm
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
RF Whatley Offline
BritBike Forum member
RF Whatley  Offline
BritBike Forum member
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
Pete -
Lucas tends to "re-cycle" wire colors across all brands and models, which makes troubleshooting mixed years and models a breeze. I.e. BRN/BLU always is the battery neg, WHT is always the switched ignition, BRN/GRN is always lighting, BRN is always the tail lamp, etc.

I tend to believe your BRN/WHT story because back in the days with ammeters in the HL shell, BRN/BLU (battery supply) turned into BRN/WHT after going through the ammeter.

So BRN/WHT has a good long history of being a negative supply line from the battery. That would explain your lights being un-controlled by the ignition switch.

bigt


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes

Moderated by  John Healy 


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