inherited a 1971 commando , need help .

I received this bike in several boxes of parts for different bikes so im not sure what even belongs to this bike. trying to install the wiring harness but not sure of the wiring that goes to the two coils and the other doo dads that are there. the rectifier wiring as well.
thanks in advance.
https://photos.app.goo.gl/cKsPCpBBXe5F1Aru7

Plenty of diagrams on the GT page.

There is probably a workshop manual here also which would include stock wiring connections.

Does the wiring layout (and wire colours) look similar to the diagram, below?
Does it still have its original contact breaker ignition or electronic ignition (as not shown in the picture)?
If it has electronic ignition then please say which type if you can?

For original contact breaker ignition, white/yellow from the handlebar kill button switch (could be the left or right-hand switch cluster as they can be reversed) connects to white/blue at the main junction area below the fuel tank where the main harness connects to the headlamp harness section, then white/blue to the ballast resistor (the white ceramic item attached to the underside of the coil bracket). White/purple from the ballast resistor to both coil negative terminals.

Black/yellow to the LH coil positive terminal and one of the two condenser tabs (housed in the rubber block next to the ballast resistor.
Black/yellow also goes to the LH points set (as you look at them from the RH side) in the points housing.
Black/white to RH coil positive, other condenser and points set.

Connect green/yellow to one of the rectifier outer terminals and white/green to the other outer terminal, brown/blue to the centre terminal and red earth/ground under the nut of the rectifier stud if red has a ring terminal.

thank you ,that looks like it.
I have a bulb in a socket that is a red wire and a browm-green stripe--where does it go ? what is it?
its ok--the light for the speedo.

where does the diode bolt onto ? and the capacitor ?

Diode, zenier? Bolts into the Z plate, big red wire goes to it.. Capacitor is usually under the seat, unless you're talking about ignition.

cheech3629 said:

I have a bulb in a socket that is a red wire and a browm-green stripe--where does it go ? what is it?

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If it's near the front end, then brown/green and red to a bulb holder is either the pilot/park light in the headlamp reflector, speedo or tachometer illumination (see the previous diagram).

I have just been given a Boyer Brandson ignition kit , does this mean i can disconnect the condenser and ballast resistor and they are no longer used?

cheech3629 said:

I have just been given a Boyer Brandson ignition kit , does this mean i can disconnect the condenser and ballast resistor and they are no longer used?

Click to expand...

Correct.

Assuming it's the most common Boyer Bransden black box Micro MkIII or MkIV ignition as there are others (red box Micro digital, and blue box Micro Power) here are the MkIII/MkIV fitting instructions.

Everything is sorted out and works except for these wires that all have spade terminals.
wh/r and wh/bla under seat by oil tank
one red wire---and two red with white stripe under fuel tank above carbs

The 2 red/white wires were for the planned (future) electric start that didn't happen until the MKIII. One of them goes to the "spare" button on the switch cluster, the other (not documented in the diagram) goes back to the battery compartment. Supposedly, the break in the middle was to accommodate some sort of lockout to prevent the starter from being engaged if the engine was running. They were taped up in the harness and never used. A red wire would be a ground, probably for the WLA.

cheech3629 said:

wh/r and wh/bla under seat by oil tank

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The white/black is, or would normally be white/purple.

cheech3629 said:

one red wire.....under fuel tank above carbs

Click to expand...

maylar said:

A red wire would be a ground, probably for the WLA.

Click to expand...

Or perhaps the head steady 'ground' if it has a ring terminal, or could be the condenser pack ground if it has a female spade (which connects to the LH/#2 coil positive for Boyer electronic ignition).

yes its the head steady ground. thanks for your help !!

cheech3629 said:

wh/r and wh/bla under seat by oil tank

Click to expand...

As LAB said, it's white/purple and would have been used to bypass the ballast resistor during electric start. The white/red is the other end of the one under the tank and would have engaged a starter relay. Both are undocumented.

DogT said:

Diode, zenier? Bolts into the Z plate, big red wire goes to it.. Capacitor is usually under the seat, unless you're talking about ignition.

Click to expand...

Dave
you’re going to blow up his zener. Brown with blue wire goes to the zener. The big red wire grounds to the Z plate at the footrest bolt.

Right, I should have looked.