Horn relay mount

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YING

YING

Pittsboro,NC
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Did a stock 1974 Commando have a horn relay?If so,where was it located?
Thanks,Mike
 
I did put a relay on my 74 to give the switch a easier time my horn seems louder to me , it was any easy figment to do
 
A relay was never fitted , but you should try fitting one regardless. Closest to the battery and horn itself. Get some real power headed into the horn instead of a circuitous route up to handlebars and back. All with those stock skinny wires.
 
Chris Zet said:
I fitted 3 relays in my electrics....for horn, low beam and high beam. works better....
Click to expand...
I am in your camp, and plan on a similar multi relay implementation. Where did you mount your relays?

Also, is there a single relay available for managing both hi/low beams?

Best.
 
RoadScholar said:
snipped

Also, is there a single relay available for managing both hi/low beams?

Best.
Click to expand...
Use a 5 terminal Bosch "ice cube" relay. They come with and without a mounting tab. With the tab makes mounting easier when used outside the headlamp shell. FYI, the steel style mounting tab is removable. Scroll about 1/3 the way down the page linked below for terminal layout.

5 Pin Relay schematic

5 Pin Mini Relay with Mounting Tab photo

5 Pin Micro Relay with Mounting Tab photo

Pin 30 is the "power in" terminal. Wire this to your headlamp ON/OFF switch or the lighting terminal on you ignition switch, depending on model year of your Norton.

Pin 85 is coil circuit ground. Simply ground this terminal

Pin 86 is coil circuit power. Wire this to your main [high] beam feed wire coming out of the Dip/Main switch inside the headlamp shell.

Pin 87 is the normally open output terminal. Connect this terminal to the main beam terminal of the headlamp bulb.

Pin 87A is the normally closed output terminal. Connect terminal to the dip [low] beam terminal of the headlamp bulb. Insulate the dip beam wire coming from the Dip/Main switch inside the headlamp shell. It is no longer needed. The dip beam will be energized directly from the main lighting switch/ignition switch.

These relays come in various sizes and amperage capacities. A 20 amp rated relay will be more than adequate for even a 100 watt Halogen main beam headlamp. If you have the room, install the relay inside the headlamp shell. That will hide the relay and simplify wiring it up. Use the "Micro" style relay if space is an issue. When you use a bulb with more than the stock 60 watt main beam, run a 14 gauge wire between pin 30 and the lighting main switch/ignition switch. Do the same for pin 87 to the main beam of the headlamp. FYI, these relays are comman as dirt, inexpensive and available from any good auto parts vendor.
 
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That eBay relay/connector combo can also be used as a 4 pin relay, for a horn. Simply connect the wire to the horn to pin 87. Leave pin 87A unused. This relay contains a resistor. Installing either a resistor or diode across the input and output pins helps prevent arcing of the contact points, thereby extending the life of the relay. Relays with resistors/diodes are preferred.
 
chaztuna said:
To avoid wiring mix ups and hacking up your stock wiring harness, use the relay connector linked below. Simply solder the Lucar "bullet" terminals to the ends of the wires. That way, you can switch back to stock wiring in the future, without any hassles.
Click to expand...

I make my own harnesses. I use the Centech AP-1 panel and plane to feed it via a separate relay to insure that the battery sees no draw when parked.

Given how dear real estate is on a Norton I was primarily interested in where members mount relays.

Best.
 
Depending on which battery you use there is some space either in the battery box or somewhere around the front of the rear fender. It's when you insist on a wet cell battery that space gets precious. For a horn relay you could also put it down by the horn with the drawback being that you have to disassemble the whole bike. :oops:
 
RoadScholar said:
I am in your camp, and plan on a similar multi relay implementation. Where did you mount your relays?

Also, is there a single relay available for managing both hi/low beams?

Best.
Click to expand...
I fitted all 3 relays in the headlamb shell....I use some low budget 4 pin working relays with mounting bracket.........pin 30: plus from battery....pin 85: minus [ground in my case] .....pin 86: signal from switch.....pin 87: signal to horn or low beam or high beam. if you are interested I can give you my [self designed] wiring diagram [for digital tacho and speedo]...
 
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RoadScholar said:
I make my own harnesses. I use the Centech AP-1 panel and plane to feed it via a separate relay to insure that the battery sees no draw when parked.

Given how dear real estate is on a Norton I was primarily interested in where members mount relays.

Best.
Click to expand...
Bill,
I don’t understand why the relay between the Centech unit and the battery.If running an electric starter,would you still have the relay?
 
gortnipper said:
Under the tank between the spine tube and two tubes that brace the headstock. Dedicated wire to the battery for the horn.
Click to expand...
Ideally you want the relay as close to the horn and battery as possible. The wire to the switch/button is less important.
 
YING said:
Bill,
I don’t understand why the relay between the Centech unit and the battery.If running an electric starter,would you still have the relay?
Click to expand...

The goal of putting a relay between the battery and the Centech is to insure zero draw when parked, no saprophytic loss. I am petty sure that OE Norton wiring harnesses may leave the charging system connected to the battery, this may not be the case with 7 pin ignition switches. Also a large number of people that replace the OE solid state charging devices with integrated reg/recs wire the out puts directly to the battery. The solid state devices in a charging system have a front to back resistance ratio which means, essentially, that they "leak". I am sure that there are others on the forum that can give you a better explanation.

With the battery totally isolated there is no leak. So I will either (or both) use a 2 pin switch that will power the relay between the battery and Centech or hide a few "kill" switches or use a programmable device that can power up the master relay. I haven't gotten to that part yet, but the goal is to isolate the battery when not in use.

Best.
 
RoadScholar said:
The goal of putting a relay between the battery and the Centech is to insure zero draw when parked, no saprophytic loss. I am petty sure that OE Norton wiring harnesses may leave the charging system connected to the battery, this may not be the case with 7 pin ignition switches. Also a large number of people that replace the OE solid state charging devices with integrated reg/recs wire the out puts directly to the battery. The solid state devices in a charging system have a front to back resistance ratio which means, essentially, that they "leak". I am sure that there are others on the forum that can give you a better explanation.

With the battery totally isolated there is no leak. So I will either (or both) use a 2 pin switch that will power the relay between the battery and Centech or hide a few "kill" switches or use a programmable device that can power up the master relay. I haven't gotten to that part yet, but the goal is to isolate the battery when not in use.

Best.
Click to expand...
Yes, slight "leak" I pull the main fuse if stored. With regular use it's not a problem.
 
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