Hi All,

Quick couple of questions - does the tail light turn off via the load shed relay during starting?  I'm looking at the wiring diagram and can't see how it does.  Just trying to understand how to re-wire with the Motogadget m-unit and remove the load shed relay.

Am I right to assume the tail light is also the number plate light?

Cheers,
Nods

The tail light unit has two bulbs in it. The lower one is a 10W [cars usually use 5W but you can also get 21W in this size bulb] and it lights the number plate from above, through the clear panel in the underside of the tail light. The upper bulb is clear 21W same as indicators. The bases of all the bulbs are the same but the 21W normally has a bigger glass on it to stop it being 'misused'. If you use the smaller glass 21W bulb in the indicators you then have an emergency spare rear light bulb or brake light bulb.

As far as I know the Load Shed Relay isolates the lighting circuits but to be honest I never checked.

Thanks a lot Olaf.

When starting one's bike it's not something that would normally be noticed - whether or not the tail light is turned off along with the head light.  Perhaps one of you kind fellows could ask your better half to have a look next time you fire up your brick?

It's not a big deal, more of a curiosity for me and to see if perhaps the BMU is doing some internal switching to turn it off.

nods wrote:- does the tail light turn off via the load shed relay during starting?

Yes.

Inge K. wrote:

nods wrote:- does the tail light turn off via the load shed relay during starting?

Yes.

Thanks Inge, but (dumb question) how?

I'm looking at the early 8 valve wiring diagram, and I can't see how the BMU is being supplied power by the output of the load shed relay.  The tail light and stop light are both powered from the BMU from what I can see.  The BMU seems to get it's power from the Green/Black wire that comes from the output of fuse #1 which is getting power from the Green/Yellow wire connected to the Emergency cutoff switch and hence the ignition circuit.

Cheers,
Nods

hi nods ...
I guess you have to remember a couple of things

generally the system electronics is off one power supply fuse ...im talking about the bmu ..ecu , instruments ..
in addition most of the load type electrics come from a secondary supply ...

I guess this is to isolate systems that need to run all the time ....and loads from those systems that they control

ie two fuses for the bmu ...might mean the bmu needs + supply to work ...but the actual load to the globes is from a second power supply - fuse

I figure that the stuff that needs to run all the time ..is unlikely to fault ...but the things that do fault ..like globe holders, globes  . brake switches and all the rest that have wiring outside of the main electronics loom ..will break the main ignition and running systems if they fault ....
far better that the load devices fuse  than take down the whole ignition system ...

hope that helps explain something of the way of thinking things through

cheers and good luck

Best thing to do is throw away the BMU and then fit LED tail lights. I have done that and it is not a big job. You don't need a BMU with LEDs as they are much more reliable than filament bulbs.

BobT wrote:Best thing to do is throw away the BMU and then fit LED tail lights. I have done that and it is not a big job. You don't need a BMU with LEDs as they are much more reliable than filament bulbs.

Cheers Bob, that's part of the plan.

charlie99 wrote:hi nods ...
I guess you have to remember a couple of things

generally the system electronics is off one power supply fuse ...im talking about the bmu ..ecu , instruments ..
in addition most of the load type electrics come from a secondary supply ...

I guess this is to isolate systems that need to run all the time ....and loads from those systems that they control

ie two fuses for the bmu ...might mean the bmu needs + supply to work ...but the actual load to the globes is from a second power supply - fuse

I figure that the stuff that needs to run all the time ..is unlikely to fault ...but the things that do fault ..like globe holders, globes  . brake switches and all the rest that have wiring outside of the main electronics loom ..will break the main ignition and running systems if they fault ....
far better that the load devices fuse  than take down the whole ignition system ...

hope that helps explain something of the way of thinking things through

cheers and good luck

I think that helps, thanks Charlie 

Basically to get rid of the load shed relay I need to turn off non-essential items during start up and ensure items that need power still have it!

nods wrote:I'm looking at the early 8 valve wiring diagram, and I can't see how the BMU is being supplied power by the output of the load shed relay.

To add to what Charlie allready said,, the BMU needs a Power supply to function (from fuse 1) .....Power to the tail light just passing through the BMU, and follows this path:
LSR-->light on/off switch-->ignition switch-->fuse 2-->BMU-->tail bulb.

nods wrote:

charlie99 wrote:hi nods ...
I guess you have to remember a couple of things

generally the system electronics is off one power supply fuse ...im talking about the bmu ..ecu , instruments ..
in addition most of the load type electrics come from a secondary supply ...

I guess this is to isolate systems that need to run all the time ....and loads from those systems that they control

ie two fuses for the bmu ...might mean the bmu needs + supply to work ...but the actual load to the globes is from a second power supply - fuse

I figure that the stuff that needs to run all the time ..is unlikely to fault ...but the things that do fault ..like globe holders, globes  . brake switches and all the rest that have wiring outside of the main electronics loom ..will break the main ignition and running systems if they fault ....
far better that the load devices fuse  than take down the whole ignition system ...

hope that helps explain something of the way of thinking things through

cheers and good luck

I think that helps, thanks Charlie 

Basically to get rid of the load shed relay I need to turn off non-essential items during start up and ensure items that need power still have it!

I think your getting the picture mate

so worst case scenario ..headlight on .(including rear lamps and all the rest - non essentials )  can wink out whilst start procedure is occurring ...saving in some cases 7- 15 amps ...which could be better used for cranking the motor ...with minimal voltage drops to the ignition "must haves " eg ignition coils ..fuel pump ecu , etc
cheers mate

Inge K. wrote:

nods wrote:I'm looking at the early 8 valve wiring diagram, and I can't see how the BMU is being supplied power by the output of the load shed relay.

To add to what Charlie allready said,, the BMU needs a Power supply to function (from fuse 1) .....Power to the tail light just passing through the BMU, and follows this path:
LSR-->light on/off switch-->ignition switch-->fuse 2-->BMU-->tail bulb.

Thanks for taking the time to explain that to me Inge - makes sense when someone spells it out.  Apologies for not seeing that path - that's the one I was wondering about.