Turning off headlight

[154048]

Greetings again, O sage advisers...

In starting the bike when it is cold, I feel like it is asking a lot to crank the starter with the 'always on' headlight blazing. Has anyone rigged a cut off switch so as to turn the 'sun' off until the bike is running?

Thanks

[lkchris]

There's a relay that cuts the headlight off while starter motor is running.

Best solution is replace handlebar switch with Euro switch that permits turning headlight on/off as you wish. If you install this, a different headlight relay is required or the headlight will always come ON when starter is cranking.

[Yarddog]

I don't care for the idea of a headlight being on while cranking, but at the same time, I'm ok with the relay doin' the job for me!!! My Harley is wired for the first ignition position being no light, light comes on second click, and like you, I prefer it thataway...however, I didn't build it faithfully to Federal standards, as the Beemers of the mid-seventies to now must be, in terms of headlights being on all the time...So, if your relay is workin', I sure wouldn't sweat it!!!

[crazydrummerdude]

There isn't a key position on your bike that'll do the trick?

My /6's have 5 positions, the 3rd being a headlight-less start.

[grahamm]

The '91 R100GS has what they call a "power shedding" relay. It turns off all the main power draw items when the starter circuit is activated...

This little relay had me puzzled in debugging my electrical system (all my lights stopped working) I could not figure out where the heck it's ground would come from ... this relay when activated provides all the juice to the lighting devices, it gets its' ground through the starter solinoid coil... so unless you have the starter installed you will not get any feed to your main electrical devices. The "power shedding" relay turns off when the starter is activated because both sides of the "power Shedding relay" are fed with +ve 12Volts... When the starter is deactived the ground to the relay is restored through the Solinoid coil.

So if you ever lose the coil on your solinoid and your light stop working this is why. Kind of a weird way to do things I'd say...

[jforgo]

There's a relay that cuts the headlight off while starter motor is running.

Best solution is replace handlebar switch with Euro switch that permits turning headlight on/off as you wish. If you install this, a different headlight relay is required or the headlight will always come ON when starter is cranking.

Another good thing about Euro switch; it allows you to be polite in crowded outdoor evening event settings, by running only parking lights - just like the courteous car people do!

[Yarddog]

Another good thing about Euro switch; it allows you to be polite in crowded outdoor evening event settings, by running only parking lights - just like the courteous car people do!

...or the Harley switch, which allows complete lights out!!! I dunno, the more I mess with my Beemer, the more I appreciate my Harley!!! They are both good scooters, glad I get 'em both...

[AnnapolisAirhead]

...or the Harley switch, which allows complete lights out!!! I dunno, the more I mess with my Beemer, the more I appreciate my Harley!!! They are both good scooters, glad I get 'em both...

My scooter allows for complete lights out too...hehe. :stick (Euro-switch)

[kstoo]

There isn't a key position on your bike that'll do the trick?

My /6's have 5 positions, the 3rd being a headlight-less start.

Your 1974 motorrads have a unique, one-year only, ignition switch. After 1974 they have 3 position key switches. I kinda liked the 1974 switch except for inadvertently leaving the taillight on sometimes and killing the battery.

[lkchris]

Your 1974 motorrads have a unique, one-year only, ignition switch. After 1974 they have 3 position key switches. I kinda liked the 1974 switch except for inadvertently leaving the taillight on sometimes and killing the battery.

This switch was used again on R80G/S, R80ST, R100GS, etc. in Euro applications. It's easy to retrofit it to USA models.

[beemerguru]

Of course the easiest way to solve the problem for post '81 bikes is to swap the grey and green wires on the back of the 3 position ignition switch.

First position,,starts, runs, brake lights, but no headlight. Perfect for off road or cold days where you don't need the headlight drain for starting or riding.

Turn to second position..headlights, starts, runs, all lights. And you can turn from first to second on the fly with no problems.

[154048]

I didn't realize that there is a out out relay.
I was thinking that the starter draw was causing the light to go out.

Sounds like I am fine. I am off to take advantage of the 50 degrees today.

Thanks

[mneblett]

Of course the easiest way to solve the problem for post '81 bikes is to swap the grey and green wires on the back of the 3 position ignition switch.

First position,,starts, runs, brake lights, but no headlight. Perfect for off road or cold days where you don't need the headlight drain for starting or riding.

Turn to second position..headlights, starts, runs, all lights. And you can turn from first to second on the fly with no problems.
Brilliant! :thumb I just went through the schematic to see why this works, and it's now obvious how this deprives/supplies the load shed relay. Definitely on my "to do" list.

But ya couldn't have posted this two days ago, *before* I put the RT fairing back on??!! ;)

Seriously, thanks for posting the idea.

Mark

[jforgo]

Brilliant! :thumb I just went through the schematic to see why this works, and it's now obvious how this deprives/supplies the load shed relay. Definitely on my "to do" list.

But ya couldn't have posted this two days ago, *before* I put the RT fairing back on??!! ;)

Seriously, thanks for posting the idea.

Mark

It's pretty easy to drop ignition switch out from the dash.

[154048]

Does this swapping of green and grey wires work on Pre 81 bikes as well?
AKA 1980? I like the idea....

[lkchris]

I just went through the schematic to see why this works ...

When a ground suddenly gets power, it's not a ground anymore.

[Yarddog]

When a ground suddenly gets power, it's not a ground anymore.

That's when a ground usually turns into a fire, in my experience...

[mneblett]

That's when a ground usually turns into a fire, in my experience...
LOL! Actooly, it's the sudden appearance of a ground where there t'weren't one a moment before that's the excitement creator :D

Eliminating a potential difference, as in the load relief relay scheme, actually takes away the opportunity for excitement under a 5+ gallon tub of fuel vapors :thumb