1972 wiring

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motorson

motorson

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I am in the middle of putting in my wiring harnes. I bought a new cloth wrapped one a few years ago before I went overseas. Now I also have a headlight harnes from Commando Specialties. All of my diagrams call for a 2 position switch in the head light except the MKIII diagram. The switch I have in my headlight is center off and left and right. (Three position?)

The handle bar switches I have are both the same with a toggle switch in the middle and two push buttons. I expect to put high/low beam on one handle bar switch and the blinkers on the other. that would leave on push button for the horn, one for flashing high beam and one for a kill button and one unused. All that leaves me wondering what the switch in the headlight is for. The '72 diagrams seem to have it for high and low beam.

Any suggestions?
 
Straight up is parking lights only and to the right is headlights on. It doesn't go to the left on mine ('72 Combat).
 
motorson said:
All of my diagrams call for a 2 position switch in the head light except the MKIII diagram.

The switch I have in my headlight is center off and left and right. (Three position?)
Click to expand...

It should be a two position switch for 1972.
A three position headlamp switch was fitted prior to 1971, so either your headlamp lighting switch is the pre-71 type, or perhaps it is a Triumph T140/T150 switch?

batrider said:
Straight up is parking lights only and to the right is headlights on. It doesn't go to the left on mine ('72 Combat).
Click to expand...

The parking lights should operate from the 4 position ignition switch on a 1971-on model.
For 1972, only the headlamp should be controlled by the switch on the headlamp shell and only when the ignition switch has been turned to the "Ignition and lights" position. On the 1971 models fitted with the two-position headlamp switch, it would have been possible to switch the headlamp on when the ignition was at the parking lights position.
 
The parking lights should operate from the 4 position ignition switch on a 1971-on model.
For 1972, only the headlamp should be controlled by the switch on the headlamp shell and only when the ignition switch has been turned to the "Ignition and lights" position. On the 1971 models fitted with the two-position headlamp switch, it would have been possible to switch the headlamp on when the ignition was at the parking lights position.
Click to expand...
Both of the '72 750s I have owned, key position 4 for parking lights the headlight will come on with the headlight toggle switch. This is normal. The '73 750 I owned did not do this.
 
illf8ed said:
Both of the '72 750s I have owned, key position 4 for parking lights the headlight will come on with the headlight toggle switch.


This is normal. This is normal. The '73 750 I owned did not do this.
Click to expand...

OK, well, that's not how it's drawn on the 1972 wiring diagram (which is no different to the 1973-74 models) as that shows the headlamp circuit is powered independently from terminal 4 of the (4-terminal 149SA) ignition switch.

With the key turned to the "Parking Lights" position (1 click anticlockwise from OFF) only Ign/Sw. terminals 1 & 3 of the 149 SA switch are common, so the headlamp circuit should not work at all if correctly connected.

According to Norton Service release N.3/36 the 4 terminal 149 SA switch switch was introduced at serial 200000 (start of 1972 production).
 
L.A.B. said:
illf8ed said:
Both of the '72 750s I have owned, key position 4 for parking lights the headlight will come on with the headlight toggle switch.


This is normal. This is normal. The '73 750 I owned did not do this.
Click to expand...

OK, well, that's not how it's drawn on the 1972 wiring diagram (which is no different to the 1973-74 models) as that shows the headlamp circuit is powered independently from terminal 4 of the (4-terminal 149SA) ignition switch.

With the key turned to the "Parking Lights" position (1 click anticlockwise from OFF) only Ign/Sw. terminals 1 & 3 of the 149 SA switch are common, so the headlamp circuit should not work at all if correctly connected.

According to Norton Service release N.3/36 the 4 terminal 149 SA switch switch was introduced at serial 200000 (start of 1972 production).
Click to expand...

Interesting. Looks like another factory manual isn't exactly what was produced. Just checked my headlight switch. The wiring harness is original to this machine and it has brown with green stripe and blue wires connected..same as the '71 wiring diagram. Both my '72s were produced late '71 (201xxx), so likely the wiring harness was from '71 production before converting to a harness with white and white/yellow wires connected to the switch.
 
illf8ed said:
Looks like another factory manual isn't exactly what was produced. Just checked my headlight switch. The wiring harness is original to this machine and it has brown with green stripe and blue wires connected..same as the '71 wiring diagram. Both my '72s were produced late '71 (201xxx), so likely the wiring harness was from '71 production before converting to a harness with white and white/yellow wires connected to the switch.
Click to expand...

Yes, it appears the switch and wiring change must have occurred sometime after 200000.

I think you mean the blue/yellow [UY] wire that connects Ign./Sw. T4 to the "two position light switch" in place of brown/green [NG] that's shown on the '71 diagram as white/yellow [WY] is the wire from the kill switch button and is on both diagrams.
 
hello folks,
can anyone share a 1972 COMPLETE wiring diagram? am doing the same job and got a bit lost...
 
L.A.B. said:
illf8ed said:
Looks like another factory manual isn't exactly what was produced. Just checked my headlight switch. The wiring harness is original to this machine and it has brown with green stripe and blue wires connected..same as the '71 wiring diagram. Both my '72s were produced late '71 (201xxx), so likely the wiring harness was from '71 production before converting to a harness with white and white/yellow wires connected to the switch.
Click to expand...

Yes, it appears the switch and wiring change must have occurred sometime after 200000.

I think you mean the blue/yellow [UY] wire that connects Ign./Sw. T4 to the "two position light switch" in place of brown/green [NG] that's shown on the '71 diagram as white/yellow [WY] is the wire from the kill switch button and is on both diagrams.
Click to expand...

At what point after 200000 is the mystery. Both of my '72s are 201xxx with what may be '71 wiring to the headlight switch. :?
 
illf8ed said:
At what point after 200000 is the mystery. Both of my '72s are 201xxx with what may be '71 wiring to the headlight switch.
Click to expand...


Further research shows the change ocurred at serial 202116 and not 200000 as quoted in the service release, so still reasonably early 1972 production.

[Edit] However, it would appear that some 201xxx serial Commandos were built after the modification was introduced, so there could have been some 201xxx bikes which had the 1972 spec. headlamp wiring and 4 terminal Ign. switch.
 
L.A.B. said:
illf8ed said:
At what point after 200000 is the mystery. Both of my '72s are 201xxx with what may be '71 wiring to the headlight switch.
Click to expand...


Further research shows the change ocurred at serial 202116 and not 200000 as quoted in the service release, so still reasonably early 1972 production.

[Edit] However, it would appear that some 201xxx serial Commandos were built after the modification was introduced, so there could have been some 201xxx bikes which had the 1972 spec. headlamp wiring and 4 terminal Ign. switch.
Click to expand...

Just to point out both my '72s have four terminal ignition switches and headllight switches on with ignition switch in the parking light position. They are stamped Sep 71 and Dec 71 and both combats. Makes the term 72 spec a bid murky. As we know Norton made changes in mid production as they saw fit.
 
Mine is 202093 built Jan. '72. It has blue and blue/yellow wires going to the headlight toggle switch. The ignition switch terminals marked 1, 2, 3 on the switch are being used. (A 4 and 5 is also stamped into the phenolic but there is nothing there to connect to.) In the parking light position I can turn the headlight on with the headlight toggle switch.

The pilot lamp is connected to the instrument lights and the tail light (all brown/green wires) on both diagrams. So the pilot light is always on when the tail light is on. It never goes off when in the PARK or LIGHTS position even if using the main headlight bulb for night driving. Something to think about if you like a new-fangled halogen pilot bulb for daytime headlight purposes. You could use a DPDT switch instead of the normal toggle switch to turn the pilot bulb off and the main headlight bulb on. I noticed a couple unconnected terminals on that switch and at the moment I don't know what they do.

Russ
 
batrider said:
You could use a DPDT switch instead of the normal toggle switch to turn the pilot bulb off and the main headlight bulb on. I noticed a couple unconnected terminals on that switch and at the moment I don't know what they do.
Click to expand...

The pre-71 switch turned off the pilot when toggled to the headlamp position, as the pilot light wire connected to terminal 6 of the 35710 switch.
http://britmoto.com/manuals/Manuals/750_man.pdf Section J Fig.J9
 
batrider said:
You could use a DPDT switch instead of the normal toggle switch to turn the pilot bulb off and the main headlight bulb on. I noticed a couple unconnected terminals on that switch and at the moment I don't know what they do.
Click to expand...

The pre-71 switch turned off the pilot when toggled to the headlamp position, as the pilot light wire connected to terminal 6 of the 35710 switch.
http://britmoto.com/manuals/Manuals/750_man.pdf Section J Fig.J9
 
Since I no longer have a stock head light with the running light in it I am wondering what I will use the switch in the headlight shell for at all. If the headlight is turned on at the ignition switch then I don't even need the switch in the headlight shell. It does look like LAB might have suggested in one post that being able to turn the head light off in either place would be good. That would also mean that it would have to be turned on in both places in order to light up but could be turned off at the ignition switch or the head light toggle switch. I’m thinking it would be best to just put a nice cover on the hole and let the ignition switch be the only way to turn on the headlight. Any thoughts?
 
motorson said:
I’m thinking it would be best to just put a nice cover on the hole and let the ignition switch be the only way to turn on the headlight. Any thoughts?
Click to expand...

Yes, you could wire the headlamp to work from the ignition switch.
 
I got the bike running today. Almost none of the wiring is stock but I did take apart a couple of old Commando wiring harnesses to get the proper color wires out. I also used the Norton connectors for most of the job. I plan to post a photo of the entire wiring harness since it seems to have worked well. Some of the main deviations from the original are: Putting the handle bar switch wires into the head light shell, the battery box, the fuse block, and the fact that the key switch only turns on the fuse block relay.

1972 wiring


1972 wiring


1972 wiring


1972 wiring


The battery box was a bit of a trick and I like how it turned out real well.
 
Is that a Fuze blocks FZ1 in front of the battery? You must let us know how you get on with that.

I'd looked at using a setup like that but was a bit concerned about the reliability of the unit. Then again lots of stuff on the(my) bike is unreliable, so it might be the best part of the design!
 
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