Wiring question

cyclegeezer · Jul 28, 2010

Was it a requirement in 1974 for the headlight to be on all the time? I'm wondering because I just replaced the wiring harness on my 74 850 Roadster and I can either have the headlight on all the time, with high beam flasher working and horn working, or I can have headlight switch control of the headlight, but without high beam flasher or horn unless the ignition switch is in the run/lights position. This change is accomplished by pulling the white wire from the left handlebar switch cluster (the one marked right in the wiring diagram). If all the white wires are connected together as the diagram shows, the headlight is on regardless of the switch position on the headlight shell, and the headlight is on whenever the ignition circuit is live. Am I missing something (besides brain cells)?

L.A.B. · Jul 28, 2010

cyclegeezer said:
Was it a requirement in 1974 for the headlight to be on all the time?

Whether it was a legal requirement or not (in whichever state/country) at the time (and it still isn't in the UK) Commandos were never wired up like that, as far as I know, (although the Canadian MkIII models had a different assimilator that switched the headlamp on as soon as the engine started) so I expect something is not connected correctly, or the harness is the wrong type?

cyclegeezer · Jul 28, 2010

I got the harness, well both harnesses, from Commando Specialties and it seemed to map up exactly to the diagram in the Clymer book. I can't really go by the old harness, it was butchered up badly, and even the ignition switch was wrong. I got a new Lucas switch that works, connects all 3 wires to power in the 4th position, only 2 in the 3rd, and only tail and pilot light in the 1st. Nothing of course in the 2nd position. I'll have the tank off again and double check.

L.A.B. · Jul 28, 2010

cyclegeezer said:
I got a new Lucas switch that works, connects all 3 wires to power in the 4th position, only 2 in the 3rd, and only tail and pilot light in the 1st. Nothing of course in the 2nd position.

It could be worth checking that the wires are connected to the correct terminals?

As the terminal sequence (1,4,3,2 clockwise) as shown on the wiring diagram does not match the actual terminal sequence of the Lucas switch, which is 1,4,2,3.

cyclegeezer · Jul 28, 2010

Thanks for the switch picture, I just checked and I've got the right wires connected to the right terminals. I may pull the left switch controls and check them for faults.

cyclegeezer · Jul 28, 2010

Found the problem, the DPO had soldered a jumper between the blue and white wires in the left handlebar switch cluster.

Diablouph · Jul 28, 2010

Anyone who is not well versed in the electrical system of a stock Norton should take L.A.B.s post, copy it, and take it to the wiring diagram. It's very easy to get the switch wired wrong.

Hobot · Jul 28, 2010

I custom wired Ms Peel with relays so headlight only came on with head light switch and key in run/lights position. I figured it'd give more juice for kick starts w/o the drain of headlight. Many will wire so just a 20 watt halogen burning when in slow traffic conditions so they don't stall on brake light drain.
Maybe why the DPO jumpered it.

hobot

Diablouph · Jul 28, 2010

Anyone who alters the stock wiring of a Commando, or half fries the wires with a short, without entry in a log, or notice in the battery box, should be executed.

OK, some may have moral objections to Capital Punishment. Life in prison without parole.

cyclegeezer · Jul 28, 2010

hobot said:
Many will wire so just a 20 watt halogen burning when in slow traffic conditions so they don't stall on brake light drain.
Maybe why the DPO jumpered it.

hobot

It did have a halogen headlight when I got it, so you may be right.

Hobot · Jul 28, 2010

I meant a 20 watt halogen PILOT light instead of the more wimpy factory one,
just in case of misunderstanding. But wiring is same as factory I believe.

I think the universal excess police wiring factory decider should be quartered.
My 2nd Combat Trixie came with custom minimalist wiring that relieved a lot of the dead end leads above, plus no signal wire clutter either. A bit pensive to try to fit hand signal inbetween clutch and bar control, but lack of signals is way down the scale of risks.

hobot

Chris T · Jul 28, 2010

What is a "DPO"?

Diablouph · Jul 28, 2010

I had to look it up. Dreaded Previous Owner. I figured PO was for previous owner, but my guesses about what the "D" stood for were a bit more colorfull.

Hobot · Jul 28, 2010

Sorry, common term on other Bike lists I had to ask about too.
D = about anything with negative connotation, dreaded, dead, departed, depressed.
Anywho I think it wise to have ability to kick or roll off start w/o headlight drain and just switch the shell toggle for travel rather than fumble key on the fly.
A pilot light is not provided for in a seal beam set up of course, so ignore me it so.

hobot

L.A.B. · Jul 29, 2010

Diablouph said:
Anyone who is not well versed in the electrical system of a stock Norton should take L.A.B.s post, copy it, and take it to the wiring diagram.

But they should note that Lucas replica switches often have a different terminal layout to the original Lucas switch shown above.

Wiring question

cyclegeezer

L.A.B.

Moderator

cyclegeezer

L.A.B.

Moderator

cyclegeezer

cyclegeezer

Diablouph

Hobot

Diablouph

cyclegeezer

Hobot

Chris T

Diablouph

Hobot

L.A.B.

Moderator

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