THUMPS
Junior Member
THUMPS, ridden by Dave
Posts: 92
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Post by THUMPS on Dec 5, 2008 13:10:01 GMT -5
Does anyone know the purpose of the regulators brown wire. It seems to be switched on and off from the ignition switch.
I am in the process of simplifying wiring and don't understand this wires purpose.
I have a pile of wire and connectors that are not in my wiring harness at present. I tied the brown and red ones together but I am uncertain.
The electrical devises power up when supplied with external power. My bike is running a capacitor. I haven't tried starting it yet.
Thanks
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Post by colinjay on Dec 5, 2008 15:47:53 GMT -5
On the 1978 SR500 ( Australian version and I presume most other versions), the Brown wire is the positive feed through out the entire wiring system. The Red wire is the batteries positive feed to/from the ignition switch.
By turning on the ignition switch, you make a connection between the Brown and Red wires. This does two things;
1st, it put power from the battery to the lights etc, via the regulator, allowing the lights etc to work when the engine is not running (powered by the battery).
2ndly, it is connects the battery to the alternator, via the regulator, allowing the battery to charge when the engine is running.
As a capacitor is effectively a small capacity electrical storage device, you would find (with the std wiring) that the lights would still work for a very short period after the engine has been stopped using the Killswitch (not the ignition switch) and that they would rapidly dim down to nothing as the capacitor discharges.
This side of the SR wiring system is totally independant of the ingition wiring, and should have no effect on the operation of the ignition.
Net result of the above: The brown wire needs to remain in the system if you want you lights and ancillery electrics to work and must still connect to the red wire (and therfore the capacitor) if you want you indicators etc to work correctly at low revs.
The std SR wiring system is very basic and there is not a lot that can be stripped from it. Pretty much, you could remove the indicators along with their associated wiring, flasher and self cancelling units, and maybe the instrument lights but that is about it.
CJ
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Post by stacer395 on Dec 5, 2008 15:53:02 GMT -5
The brown wire is the active for the brake light switch's, flasher relay, horn, taco, etc, when the ignition/main switch is turn on.
Steve.
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THUMPS
Junior Member
THUMPS, ridden by Dave
Posts: 92
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Post by THUMPS on Dec 5, 2008 18:08:08 GMT -5
Thanks a lot.
I have removed ignition switch, instruments, kill switch, turn indicators and their timing circuits, as well as previously mentioned battery. I am planning on running a trail tech vapor for instruments. Adding new neutral light and high beam indicator light.
I figure that I have a mechanical kill switch with the decompression lever. I still need to make a tachometer cable cut off plug for the cylinder head.
I probably took out half of the wiring or more.
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Post by aero on Dec 6, 2008 7:03:29 GMT -5
Well...almost right guys  . The brown wire connection has a subtle function that is important to the correct operation of the regulator. What it is doing is sensing the voltage on the consumer circuit. As quite rightly pointed out the brown wire feeds (what I call) switched battery voltage from the ignition switch to everything that needs power. So the brown is the main feed for everything on your bike. The regulator's output is the RED wire. So why on earth if the output is the red wire do you need the brown connection on the regulator? Its simple, the SR's regulator is a refined design that gives very controlled output. To give such precise control the brown wire is used to sense the voltage on the load side of the circuit, rather then at the the output of the regulator. Its feed back if you like. So you can connect the brown to the red on the regulator, but you will be sensing directly the regulator's output and is not as precise as measuring from the load side. Definately not a good idea when running a capacitor as you will need accurate voltage control. Capacitors, unlike a battery only have a very limited power storage ability so the regulator will have to react quickly to keep up. You could look at it like this - If you are the red wire - you yourself know how hard you're pissing. The brown wire is a person you're pissing on - confirming to you how hard you're pissing. So you know if you need to piss faster or not to get the desired effect. If he stops telling you you only think you're pissing enough. Most of the time you will be right, but better to know for sure. Here's a diagram I did for a XT500 converted to 12 volts. Different generator and ignition to the SR, but the lights will be the same. The regulator I used on this is a cheaper unit that doesn't have the sense line, works well enough without the feedback  .  I work too many nightshifts |
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THUMPS
Junior Member
THUMPS, ridden by Dave
Posts: 92
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Post by THUMPS on Dec 6, 2008 22:25:49 GMT -5
Hey thanks Aero for the template. Hope you don't mind the plagiarism. Here is my schematic, the color code is what I used.  My harness is basically done except for some shortening of wire. I used stock connectors throughout. Maintained the stock magneto wiring. It has been too cold for prolonged outside work. |
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Post by curly001 on Dec 8, 2008 5:43:09 GMT -5
Thumps can see a couple of problems
1. You need a kill switch/Ignition switch to stop the motor you can't use the decompressor to stop the motor. You will bend a valve at the very least.
2. I was running a very similar wiring system to the one you are going to use and kept blowing lights. On stopping the voltage spikes to around 36volts and blows bulbs gets very expensive at $25oz a headlight bulb. Yes you can turn off the headlight switch, but you will forget and it becomes a real pain. The simple solution is have a combined power/engine stop switch(Ignition)
Curly
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Post by aero on Dec 8, 2008 6:39:39 GMT -5
Some way of switching the lights off would be an idea. You have to consider what happens when you get a fault AS WELL. Being able to switch stuff on and off is very handy!
I used an ignition switch from a moped, most mopeds seem to have a magneto and therefore in the off position there is one set of contacts that are closed, providing means of earthing out the sparks. The SR cdi works in the same way, the black and white wire is shorted to the frame when off.
I know relays make things look complicated but they give you 100% brighter lights and allow you to have fewer wires running to the handle bars. Also those wires can be very thin as there is very little current needed to operate a relay. My street tracker will have 3 relays, two for the lights and one on the horn. There will be very little wiring on the bike as you can use a car type relay box as a bus bar system for your main power with just the lights etc coming off that.
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THUMPS
Junior Member
THUMPS, ridden by Dave
Posts: 92
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Post by THUMPS on Dec 8, 2008 14:20:40 GMT -5
Thanks for your concerns. I have many times killed my engine with the lever. So far no problems. My engine is stock 9:1. My bike didnt have [edit] kill switch when I got it, as the prior owner had put an aftermarket throttle. I would typically turn it off with the key or just pull on the decompression lever. My bike doesnt have a headlight switch either, it was designed to run with the ignition switch on. I don't plan on running any relays. It adds complexity to the design. I keep thinking of the 24 gauge solid wires in the relay coils breaking from vibration and it is not important to have brighter lights as I don't ride at night. Think whitetail deer. So far I have hit two in three years, fortunately in my truck. Burning headlights out would be an issue. If that happens I will add a SPDT toggle switch.  |
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Post by solo2racr on Dec 8, 2008 17:46:42 GMT -5
I never imagined a little brown wire getting so much ink. ;D
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Post by aero on Dec 8, 2008 18:55:45 GMT -5
You mean electrodes......this is electric paper, no?  |
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THUMPS
Junior Member
THUMPS, ridden by Dave
Posts: 92
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Post by THUMPS on Dec 8, 2008 20:41:43 GMT -5
Aero says:
You mean electrodes.....
I think we all mean electrons.
Electrons move from minus to plus don't they?
It has been a worthwhile discussion for myself and hopefully others.
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