master switch wiring

Hi guys I am just new to the forum l have just bought a 1972 interstate which has just had a make over .My problem is l had to go to the second key position to start it which meant running with the lights on in trying to rewire it l seem to be makeing a hash of it .The problem is on the switch how do l know which connector is the first or the second as there is no markings , at the moment l have the blue brown and the white on what l thought was the first position because with out the white on the bike will not start and the only way to stop it is to remove the white lead . l think i will be buying a new switch as the key will not come out if you turn it anti clockwise , any ideas anybody .I also have a blue yellow wire which l can,t find on my wiring diagram.

Keith,

If you look on the terminal end of the switch you should see numbers (1-2-3-4) stamped near the terminal spades, (some are double spades)?

So, for 1972 you should have a brown/blue (NU) wire to the number 1 terminal, double white (W) to T2, brown/green (NG) to T3, and blue/yellow (UY) to T4. If you cannot find a blue/yellow (UY) wire on your diagram maybe you are not using the correct diagram?
There is a chance of course that the switch unit is faulty and the wires have been swapped around?
If you cannot find these numbers near the terminals then re-post and I will give the 'clock' positions for the wiring connectors.

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Addition

There is a chance that the switch you have is not the correct one!
How many switch key positions are there?

master ignition switch

Thanks for your swift reply the switch has in fact got 4 terminals all double the fact that it has been wired up to work only with the lights on makes me think it has had a problem before , the fact that none of the terminals are marked and you cannot remove the key from any other position apart from the one where you insert it makes it hard to figure out which is what number terminal .I intend to get a new one from rgm ,it just frustrating not being able to ride it .I live very near Heartbeat country and am looking forward to parking it up outside the Aidensfield Arms. Cheers thanks for your help . The clock position would be a great help . Thanks again Keith

Re: master ignition switch

keith said:

The clock position would be a great help .

Click to expand...

I will assume you have what should be the correct four key-position (L to R = park--off--ignition--ign+lights) switch unit which is a 149SA type with seven spades? (you said: "4 terminals all double" Are you sure there isn't one single?).

Looking at the switch terminal end and working from the largest gap between them in clockwise rotation you should wire up as follows:

T1 (2x spades) = brown/blue wire.

T4 (single spade) = blue/yellow.

T2 (2x spades) = white.

T3 (2x spades) = brown/green.

Of course if you want to temporarily bypass the switch so you can do some riding just remove the wires from the switch and connect the brown/blue wire to the white wire, that will give normal ignition. Connecting all four wire colours together will add the lights.

Don't leave it parked like that though, either disconnect the brown/blue wire, or battery wire, or remove the fuse.

hello this is my first post to this forum. I have recently purchased a 72 roadster that " needs" a lot of ( tlc) tender loving care.
that being said . can you tell me if the instructions for wiring the ignition switch apply to a (7) seven spade switch ? I have spark to the left plug but not the right plug, I have a battery light that works in the headlight & the horn works no headlight or tail light or brake light . this bike is not fitted with turn blinkers. I have oem header pipes as well as a new set of oem peashooters but no mounting brackets & I'll need a seat, however most of the bike is all there including a new looking mikuni single carb & manifold. my question now is am I to look at the switch from the rear ( spade side ) & follow clockwise ( left to right from the gap in the spades ? ) or do I look for a picture somewhere ?
lucas electrics ( aka prince of darkness ) have always baffeled me every since I toasted the wiring in my old bsa. thanks for your patience Ray

Welcome to the forum.

krazyray said:

can you tell me if the instructions for wiring the ignition switch apply to a (7) seven spade switch ?

my question now is am I to look at the switch from the rear ( spade side ) & follow clockwise ( left to right from the gap in the spades ? ) or do I look for a picture somewhere ?

Click to expand...

Terminals 1, 2, & 3 each have common pairs of spades, so there are only 4 terminal positions in total. Terminal 4 being the odd one with the single spade.

wow how simple is that !! thanks Ray

Hi All,
So what does each terminal do?
Terminal 1 = Power in from battery and power box?
Terminal 2 = Power out when in key first clik position = Ignition, Brake light and horn?
Terminal 3 = Power out when in key second click position = All on terminal 2 are powered on plus lights?
Terminal 4 = Parking lights???

Thanks for corrections
Regards
Staytite

Staytite said:

Terminal 1 = Power in from battery and power box?
Terminal 2 = Power out when in key first clik position = Ignition, Brake light and horn?

Click to expand...

Correct.

Staytite said:

Terminal 3 = Power out when in key second click position = All on terminal 2 are powered on plus lights?

Click to expand...

T3 = Power out to lights except headlamp.

Staytite said:

Terminal 4 = Parking lights???

Click to expand...

T4 = Power out to headlamp.

Common terminals at key positions :

Parking lights = T1-T3
Ignition = T1-T2,
Ignition & lights T1-T2-T3-T4