750 Sport Wiring Questions ??

Gum · Post by **Gum** » Sat Oct 23, 2010 1:27 am

Gday, im wiring up my 73 Sport, I have red wire from the coils, [ Tacho ] and a blue ??????. Does anyone know what this blue does, its goes up into the headlight.

Also the three lights in the headlight shell, what do they do, High beam and ????

Thanks Gum

machten · Post by **machten** » Sat Oct 23, 2010 2:14 am

My sport has been rewired, so I can't be sure on the colours. On mine the blue is a common power to the high/low switch and then green and yellow wires from there into the headlight globe poles. US wiring may also have been different. I seem to have in my mind they didn't have park lights for some reason, but I'm not sure.

The three lights from left to right as you sit on the bike are:

red - high beam
white - ignition on
green - lights and/or park light

Kev

Gum · Post by **Gum** » Sat Oct 23, 2010 4:27 am

That makes sense, it must go on the positive of one of the coils, then to the idiot light that is the Ignition on.

Now what is this Park Light, what would feed that, the IGN key is a 3 way key but it seems only to work on On and Off.

Now the Key in the headlight, that just turns the lights on and off, [ now parking lights there ????????? ]

Thanks Gum

machten · Post by **machten** » Sat Oct 23, 2010 5:05 am

Yes, it is a three way switch. I'm not sure if this should happen, but here's what happens on mine:

Centre is lights off - start from there.
Turn it the right (anti - clockwise) is park - tail light and seperate park globe in the headlight comes on (key on or off) (my instrument lights come on as well (tacho and speedo), not sure if this right.
Turn it right - headlights on. At that point you can use the Hi/Lo switch to change. If I turn the key off at this point, it reverts to the park circuit only.

My recollecion was that in the US, park lights were illegal at the time. Also, US bikes may have had the indicator circuit (which was always available from the fuse box and I think from the wiring loom) used. Sorry Gum if that is a bit hazy. I'm sure others on this site will be able to give a better steer.

Kev

Steve Foster · Post by **Steve Foster** » Sat Oct 23, 2010 5:23 am

I'm not sure if this should happen, but here's what happens on mine:

Ditto.
Steve.

Gum · Post by **Gum** » Sat Oct 23, 2010 5:35 am

I think this is going to harder than I thought. All my manuals are wrong as far as my bike goes. One question, I have heavy wires that go from the fuse box to the headlight. Do they go direct to that switch [ the one with the key ] then to the headlight or run through a relay. Some of my books show a relay, but I dont have one. Also the orange wire from the fuse box that runs into the headlight is live all the time ?????? Why the hell would that be. [ you going to say to run the park light ] buts it a very heavy wire to run a small globe. Also does your rear light come on with the park light

Thanks Gum

machten · Post by **machten** » Sat Oct 23, 2010 5:55 am

If it makes you feel any better Gum, I have a friend putting together a new wiring loom for a 73 Sport right now. As far as he knows (and he bought it about 1976) the loom is stock. The colours dont perfectly match the 73 wiring diagram for Euopean Sports. Not a lot of diff, but an annoying few.

You can be assured there was no "heavier wire" used as stock - absolutely for sure. For the rest, get a diagram, a multimeter, and a bunch of time - and you'll work it out!

Kev

machten · Post by **machten** » Sat Oct 23, 2010 6:03 am

Sorry, in response to one of your questions - there was no relay as stock, but it was a common mod afterwards.

Kev

Gum · Post by **Gum** » Sat Oct 23, 2010 6:05 am

I have all that gear, the diagrams are mostly a waste. When I say heavy, I mean one of the main wires from the fuse box, there are some heavy one there. One is Orange and live all the time.

Main thing is does it have relay for the headlight ??? Its the only thing that concerns me as far as load goes.

Thanks Gum

machten · Post by **machten** » Sat Oct 23, 2010 6:19 am

Gum,

can't say without seeing where is coming from the fuse box and what is going into it on the other side. What fuse number is it on?

There is no relay anywhere as stock.

Kev

machten · Post by **machten** » Sat Oct 23, 2010 6:27 am

Of course you need one common live all the time out of your fuse box with the ignition on - or it won't work at all! You also have one circuit powered key on or off - that powers the park circuit lights.

Kev

machten · Post by **machten** » Sat Oct 23, 2010 6:38 am

Just to calrify something Gum. I know you have a US imported bike - are you saying you have a 3 position ignition switch and a two position light switch?

Kev

Gum · Post by **Gum** » Sat Oct 23, 2010 3:38 pm

After brecky I will have a look, I think the headlight switch is only 2 position. The key is 3, 2 are of and 1 is on. Saying that on the 2 off positions there is still that live feed. [ that will be my park lights.

You talk about a USA model. I dont believe there is one, nor this is one. It was unpacked by the owner who bought it in from Itlay, I dont think it came thru a Shop, also it has Metric speedo, as we all know a US bike would be in MPH.

Thanks Gum

Gum · Post by **Gum** » Sat Oct 23, 2010 4:18 pm

Ok, I have had a look, and yes the Headlight Switch is 3 position, just very sticky and stiff at this stage on one side. I think with no relays and now knowing what does what I can continue wiring it up. Thanks to all, Im sure I will have more questions soon, like this one.

Any fool proof way to get the coils right, I have fitted Dyna Ignition, so which wires to the rear cyl and front cyl.

Thanks Gum

Gum · Post by **Gum** » Sat Oct 23, 2010 5:53 pm

Does anyone know where the White wire goes from the Tacho ???

Its has a light, got that,

A red wire [ pulse ] from the coil,

A white to [ but dont know where it goes from there ]

Then there is a black, [ earth ]

So that is 4 wires, but only 3 connectors on the Tacho. ??????

Thanks Gum

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750 Sport Wiring Questions ??

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