pardon my dumb (again)

i was under the impression that my '70 cmdo had a positive ground. but the red wiresgo to the the( +) terminal and the black wire goes to the( -) terminal. the volt meter verifies the polarity. a bit concerned the the ohm meteer shows no continuity to either the engine or the frame with the (-) terminal.

black wire to neg terminal


red wires to (+) ternimal


also what's this terminal block for and what's supposed to go the exposed blade connector on top of it?


thx,
go

The red wire should go to the (+) terminal of the battery. That is ground (or also known as positive earth). Check continuity between it and the red wire that goes to the rocker spindle cover on the right side (does in my year anyway). Black shouldn't have much going on unless the wire you're checking is "hot" by key or whatever.

goo said:

i was under the impression that my '70 cmdo had a positive ground. but the red wiresgo to the the( +) terminal and the black wire goes to the( -) terminal. the volt meter verifies the polarity.

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Red to battery positive would be correct if it is wired positive ground.

The brown/blue wire (with fuse) should go to battery negative (or is the brown/blue wire connected to the black battery wire)?

thanks, i thought the black wire should be ground.

The "terminal block" is the rectifier. The exposed spade is a ground wire connection.

Thanks Benfranklin, bless his heart for the confusing meanings of polarity terms and return paths. Our Brit Iron uses where the electrons are emmitted as the + sprayer terminal while Brit - is the positive lack of electrons sucker terminal. You don't want your Norton - wires to ever show continuity to the + frame Earth, until the component the - wire feeds is switched on. Don't worry if ya put in battery wrong, either smoke a bit then blows the fuse or starts such a small fire any ole extinguisher can catch it in time, Then just put more wires back and try again. Only someone that shouldn't be allowed to own a Norton would do that of course...

thanks again, gents

lucas theory

http://www.mez.co.uk/lucas.html

The wires don't care what color they are, it depends on which which battery terminal is connected to ground or earth that determines pos or neg earth. If you look up around where your coils are, you should find 2 pair of red wires (that's 4 wires all together, 2 connected to one terminal and they all come from the battery pos) and both of those ring terminals should be connected to a ground point on the coil mount somewhere, or it may be connected to the headsteady bolts. I'd like to know where those are connected on your bike. Here's where I connected mine (under the capacitors on each side), but I'm not convinced that's where they went originally, but they work fine there. On your model, there is also supposed to be a wire from one of the sidestand bolts to the bottom engine mounting stud, but mine works without it. It's supposed to supply the frame with ground or pos in your case. It might be wise to put your ohm meter with the fuse out, one lead on where the red wires connect as above and check all the ground points around your bike, like the fenders, engine, exhaust, anyplace you can find that would be 'earth', and make sure you don't have any points that are ungrounded.

That unconnected lug on the rectifier is not used on your model, but it's just another ground point. Nothing unusual about that.



Dave
69S

DogT said:

.... I'd like to know where those are connected on your bike. Here's where I connected mine (under the capacitors on each side), but I'm not convinced that's where they went originally, but they work fine there. ...

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Dave, obviously by '75 the wiring might differ, but my MKIII has (had since I'm rewiring) those connected to a lug standing out a bit proud of the rear, black-painted part where coils bolt up. Assuming it's true that a pic is worth a thousand words...

Lee, the 69/70 doesn't even have those parts, but thanks. I went around with this a couple of years ago and never came up with a definite answer. I had notes of when I took it apart and the only thing within reaching distance of the ring connectors on the wires that will fit is where I put it and it sort of matches with my notes, but others have it connected to the Allen bolts into the head, but my rings are too small for that. I'm sure a lot of them have been changed over the years, but I'm certain the ring connectors on mine are original. I just would like to know if there is another 69/70 out there with the same connections.

Dave
69S

DogT said:

Lee, the 69/70 doesn't even have those parts, but thanks. ...

Click to expand...

OK, let me try again a different way. It seems from the image from a 1970 brochure below you have it right (or at least pretty darn close).

Yeah, I've seen that. I guess I'm just beating a dead horse but would like a confirmation from someone else that has one.

Thanks,
Dave