1971 Build for Dad

[Jim]

Just noticed... headlight, meters and tail are all lit as soon as you turn the key on... you lost the on/off function. It's late... I'll look again tomorrow.

OK... so the blue wire coming out of the fuse block will power the tail and meter lights as soon as you turn the key on. That wire needs removing (black x's). The lights are already fused by the red/yellow wire from the fuse block, so it's not needed anyway. If you want to restore the Park function of the iggy sw, you'll need to add the blue wire back there (at the switch). For protection, you could add a small in-line fuse in the headlight bucket. Doubt it would ever blow 'cause I doubt you'd ever switch the key to Park in the first place.

 

[Paul Sutton]

I am not sure about the 3 pin flasher replay?? Is it on all the time?? Should that be earthed?? I use the 2 pin relays which just have an input and output to the indicator switch so this 3 pin seems unusual to me.

 

[Jim]

Maybe this will help Rhy. Pop quiz time...
What can you tell me about the switch below?

 

[Rhy650]

you were being called on. It's an effective way of learning.

I had this coming... I taught college Biology for years and preyed on many a freshman.

You lost power to the brake sw and neutral light...

the blue wire coming out of the fuse block

This park feature and the blue wire have been confusing. I don't see why I would ever need the park feature on the ignition? In it's original form the ignition switch powered the blue wire, but it seems that the headlight switch also provides power once the ignition is switched to On?

What can you tell me about the switch below?

I have a feeling I am about to learn something here! This switch provides power for the headlights through the blue/black wire and also powers the blue wire. A single-pole double-throw switch? ...?

In all seriousness, thanks for the help! This clearly would have been a disaster if left to my own devices!

 

[Jim]

I had this coming... I taught college Biology for years and preyed on many a freshman.

This park feature and the blue wire have been confusing. I don't see why I would ever need the park feature on the ignition? In it's original form the ignition switch powered the blue wire, but it seems that the headlight switch also provides power once the ignition is switched to On?

Correct. The way you have it drawn, the iggy sw powers the fuse block with the brown wire. The fuse block then sends power to the light sw on the red/yellow wire... and yes, that's all you need. If you don't want the Park function, just don't add the blue wire I re-added to you schematic.

I have a feeling I am about to learn something here! This switch provides power for the headlights through the blue/black wire and also powers the blue wire. A single-pole double-throw switch? ...?

Correct again. Minor correction; the blue/black supplies power to the dimmer switch..... and then on to the headlight. The point I was trying to make is the yellow dots in the matrix indicate a switch connection (continuity). So for any switch, chase the wires until you find the one going back to power (fuse)... that's your starting point. Now, follow it back to a switch and connect the (yellow) dots. Follow those wires out and you come to the component(s) being powered. Look to the right on the matrix and there's your function. In this case the OFF position has no yellow dots across it.... power comes in and stops... nothing goes out. the ON function has dots on all 3 blocks... power in on one and out the other two.

Here's another exercise: The dimmer switch has two functions listed in the right of the matrix. Explain what they do.

 

[Paul Sutton]

With the Ignition Switch in Park Position:
1. In the Park Position current is drawn from Battery via 20A fuse to the ignition switch and then energizes the thick Blue wire to light the tail light.
2. But there is a feedback loop in your circuit.
3. The current can flow back up the Blue wire to the headlight switch.
4. If the headlight switch is set to the ON position then the current feeds back through the switch and down the Red/Yellow wire to the fuse box.
5. At the fuse box the current then energizes every circuit.

If you park the bike at night and put the ignition switch in the Park Position then I can come along, flick the headlights on, and ride off on your bike. The way to break this feedback is to insert a 4A Silicon Diode in the blue wire to the Headlight switch..

 

[Jim]

The way to break this feedback is to insert a 4A Silicon Diode in the blue and Blue/Black wires to the Headlight switch..

Or just delete the Park function.

 

[Paul Sutton]

On my Virago I had a similar issue trying to power the tail light from the Hi and Low switch. Of course this could have feed current from the Hi filament back through the Low etc. Because the tail light is low wattage I just put in two 4A diodes to stop feedback. On my 81 Special I had always wondered if Yamaha deliberately had the tail light come on when the ignition was turned to start just to avoid feedback loops and the use of diodes. Recently I have been considering removing the diodes and having the tail light power on whether or not the head light is on or off.

Edit: Sorry Jim but I had to edit the post. There needs to be a diode on Blue and Blue/Black wire to prevent feedback down the Red/Yellow.

 

[Jim]

Edit: Sorry Jim but I had to edit the post. There needs to be a diode on Blue and Blue/Black wire to prevent feedback down the Red/Yellow.

I fixed your quote in my comment.

 

[Paul Sutton]

With the Blue/Black wire a 4A Diode will not do because this feeds back to the Head Light via the Dimmer Switch. Maybe in this case Jim is correct and the thick Blue wire should just be snipped.

I think I see a solution but need to think on it. Feedback loops really need a fresh brain to puzzle through. If you need/want to retain the rear park light facility then it will require the use of a diode. I'll get back about this tomorrow.

 

[650Skull]

I'm not the wiring smart one so cut me some slack guys..........Wouldn't this solve the issue of the powered loop and retain the park option............Using the SH diagram, showing the R from battery to ignition, on its own Fuse through the fuse block, to the ignition and back to the fuse block on the brown wire, Where it then breaks off into all the other fussed circuits through the fuse block.

Power on the L wire, Gauge and taillights, (this can be run through an on/off switch as well), is only active when the key is in the on or park position. Power on the Br wire that feeds everything else on the bike is only on when the Key is in the on position

 

[Paul Sutton]

I think this is the solution using one 4A diode:

Just one diode in that section of the Blue wire stops feedback to the Head Light switch. This then means the Park Light facility is retained and no feedback goes via the switch down the Blue/Black and the Red/Yellow wires. Have a good think through this solution because my brain is dying.

Note: When Park Light is ON the instrument lights are also on. Is that desired?? The cross relates to an earlier error in the diagram.

 

[Paul Sutton]

With a clearer mind I see the following scenarios:

1. No parking light option: Cut the thick Blue wire at the ignition.

Impact - Tail light only on when the headlights switched is on.

2. Parking light on but without Instruments lights on: The thick Blue wire from the ignition switch should feed directly to the tail light and preferably via a fuse. This requires making a cut in the Blue wire to separate the Park switch from the Headlight switch.

Impact - Tail light is on with ignition in Park and also when ignition is ON i.e. tail light is always on independent of the Headlight switch. Also instrument lights are only on when Headlight switch is on.

3. Parking Light on with instrument lights also on: Insert 4A diode as mentioned previously and preferably add a fuse to the thick Blue wire at the ignition switch.

That's it from me.

 

[5twins]

Just to clarify (or maybe confuse, lol) matters a bit more, I'm not sure what diagram you modded to make yours but the ignition switch rendering is not correct for your early model. Your drawing shows the later type switch that turns the tail light on when the switch is in the "On" position. Early switches weren't like that, they only powered the tail light in the "Park" position .....

I'm guessing this feedback loop wasn't an issue on these early models because there was only one fuse. And it seems I may have inadvertently created it on my '83 when I added an earlier headlight on/off switch. Honestly, it's not something I even checked for because I wasn't aware of it. Looks like I'll need to do that, put the key in the "Park" position, turn the headlight switch on, and see if the rest of the bike is powered through that feedback. If it is then I guess I need a diode. Paul, could you provide a bit more info on that, and maybe a link to something suitable?

 

[Rhy650]

The dimmer switch has two functions listed in the right of the matrix. Explain what they do.

Power flows into the dimmer through the blue/black wire. The two settings of the switch complete one of two possible circuits that result in varying voltages (or is it current?) being sent to the headlight, with the green wire having a higher voltage in the yellow wire. Something like that?

Feedback loops really need a fresh brain to puzzle through

Definitely, I find it much easier to think of current flowing in only one direction, too bad it doesn't!

Wouldn't this solve the issue of the powered loop and retain the park option

I am certainly no expert on this, that has been well-established here! However, I don't think this will work due to the type of fuse box I am using. It is not capable of multiple "inline" fused circuits. Power goes in and is distributed through a gang, with each outgoing connection being fused. I believe that setup would also subject the main 20A fuse to a short in the taillight/gauge, which we are trying to avoid. The real problem is how the headlight switch and ignition are both supplying power to the blue wire.

I'm not sure what diagram you modded to make yours but the ignition switch rendering is not correct for your early model.

The switch blocks I have are for a later model, this thing is a Frankenstein!

2. Parking light on but without Instruments lights on: The thick Blue wire from the ignition switch should feed directly to the tail light and preferably via a fuse. This requires making a cut in the Blue wire to separate the Park switch from the Headlight switch.

This is the solution I like the best. It might be nice to have the taillight on as a park indicator. It would also only turn on the meter lights if the headlight was on, which seems logical to me. Here is an updated diagram:

I'm glad we ended up working this out, as the fuse box used above is going to fit much better in my setup. I got in a fight with some sheet metal yesterday and came up with this "structure" to mount most of the electronics in front of the battery box:

 

[GLJ]

Are you using the original 71 ignition switch and headlite switch?

 

[Rhy650]

Are you using the original 71 ignition switch and headlite switch?

Ignition - Yes
Headlight - No

 

[Jim]

Power flows into the dimmer through the blue/black wire. The two settings of the switch complete one of two possible circuits that result in varying voltages (or is it current?) being sent to the headlight,

Correct. For most practical purposes, you can think of it as current or voltage. Yes, there is a difference, but as long as flow direction is all you're trying to figure out, it doesn't matter. Some of my students would liken it to water (or hydraulic) flow through various hoses. As long as all you're trying to determine is what power goes where, use whatever visualization works for you.

...with the green wire having a higher voltage in the yellow wire. Something like that?

Nope... nothing in a switch will increase or decrease the voltage (unless there's a fault in the switch). The headlight itself has two elements, high and low. The high beam is brighter because it uses more power than the low. The switch just controls which element it will send that power to. The high beam element has less resistance than the low. Less resistance means more power (current (amps)) can flow.

Here is an updated diagram:

Initial impression is it looks good. I'll study it in more detail later.

I got in a fight with some sheet metal yesterday and came up with this "structure"

Looks like you whooped it pretty good.

 

[Rhy650]

The headlight itself has two elements

That would make MUCH more sense than some elaborate switch dimmer system...

 

[5twins]

If the ignition switch is the original then it will be like the one I showed you, not like the one in your drawing. It won't power the blue wire in the "On" position like the one in your drawing does, only in the "Park" position. That means you can't use it like you're wanting to, to power the tail light in the "On" position. Here's how a '77 main switch and headlight on/off switch are wired. Tail light power from the headlight on/off switch on the blue wire is spliced into the blue wire coming out of the main switch. From there, a line runs back to the tail light. But, doing it this way with a multi-fuse box apparently is going to create that feedback loop that was mentioned .....