This mod is to enable the bike to be started without the headlight on but without having to add an additional switch.
And still retaining both hi and low beams.

Its in response to a thread started by WestOz but I thought I would start a new thread so everyone who's interested can see how its done.
Or should I say, how I did it.

This is the basic circuit.
Its the simplest circuit I could come up with.


Its not difficult so don't be put off.
I had come up with a few other circuits but they were either more complicated and/or were more involved in wiring it up.
It also benefits from using a single pole relay.
I thought this was important as most weather resistant, cheap, auto relays were single pole.

This circuit is not only very simple, it is easily wired up to only the 3 wires that go to the headlight bulb which will make installation very easy.
No need to chase back into the loom chasing a b+ or something.

You need 1 general automotive relay and 2 general purpose diodes.
The relay I used was one I picked up from a general auto accessory store for $A10.
The diodes I used were IN4004's but any general purpose power diode will do.
Any electronics hobby shop will have them.


(the pic shows 3 diodes but you really only need 2)

I soldered everything directly to the relay.

Solder the cathodes of both diodes to one side of the coil on the relay.
The cathode is marked with a white or silver band.


Then I soldered 5 lengths of wire.
1 on to each anode (the other end) of each diode(in the pic below they are the orange and brown wires).
1 to the other side of the relay coil.
And one to each side of the relay contacts.


Then I used some heat shrink tube, electrical tape and cable ties to insulate the terminals and clean it up.


You should have 5 wires now coming from the relay/diode assembly.
2 coming from the 2 diodes(anode side), 2 coming from the relay contacts and one coming from the coil on the relay. The one coming from the coil should be connected to the coil terminal opposite the one to which the diodes are soldered.

Now, I have a Acerbis Dimension headlight but the method is the same.

Find a place in the headlight assembly to mount the relay and wire it in.


You only need to really cut one wire and that is the wire that goes to the high beam filament.
Cut this wire.
Connect the wire that leads to the bulb to one of the leads that is connected to one of the diodes (it doesn't matter which one) and also connect the lead that goes to one of the relay contacts (again it doesn't matter which one).
Just so I'm clear, this connection is of 3 wires.
1 goes to the high beam filament, 1 goes to the anode of one of the diodes and the 3rd goes to one of the relay contacts.
Tape it up as we are done here.

You should have 3 wires left.

The wire coming from the other diode is connected to the wire that goes to the low filament of the bulb.
No need to cut it, just strip back, wrap, solder and tape.

The wire coming from the coil of the relay goes to the earth return wire that is connected to the bulb using the same method as above.

The last remaining wire is connected to the cut wire that goes back into the loom. The hi beam wire you cut earlier.

Tape and wire tie as required but that's it.
Done.

Now, if you switch the bike on with the hi/low switch in the high position, the headlight should remain off.
Well mine does.

Then, when you switch it to low beam, the headlight should light up.
Switching back to high should light the hi beam.

Job done.

I have done the best at describing what I did but my headlight set up was already modified.

I think its a very cheap worth while mod.

The headlight can now be left off until the bike is running and you're ready to turn it on.

 

Nice job

 

Genius.

 

Good job!

 

I'm confused.......so does the light stay off until you perform another action? In other words is there a chance that you could take off with the light not on? That would not only be illegal here but dangerous. But I could have read all of that wrong.

 

The light will stay off until you switch the hi beam to low beam.
If you don't do that the light stays on.
But once its on it works as per normal.

Do you have compulsory lights on for motorcycles?

 

All of Australia does

 

All bikes on the road here in Washington are required to have their headlights on at all times.

 

same here in cali, and i think most the us.
(420th post, just had to point that out for jrock)

 

checking to make sure the front light is working is just one of the safety checks I make before I ride anyway. THis mod wouldnt affect that at all. Dont trust your light to come on every time.