Author Topic: question about a new horn (update....put on relay) (Read 3059 times)

andy8190 · « **on:** February 24, 2009, 07:49:05 PM »

i went to oreillys today and got a horn that looks similar to the stock horn and put it on my bike because mine were not running. my question is will it burn the button if i just hooked it up straight from the stock wires?

OldSchool_IsCool · « **Reply #1 on:** February 24, 2009, 07:56:53 PM »

Guess it would depend on the current draw of the new horn vs the stocker. You can measure the resistance of the two horns and if the new one is a lot less, then you may have an issue. Also, if the contacts of your horn button are corroded, then the corrosion will add resistance and that means heat.

Considering hos short one uses their horn NEEP NEEP! I doubt the contacts would be together long enough to burn up ur button.

andy8190 · « **Reply #2 on:** February 24, 2009, 08:22:04 PM »

ok good deal

Patrick · « **Reply #3 on:** February 24, 2009, 09:42:05 PM »

When I put louder aftermarket horns on my K5 750 I ran a fused wire directly from the positive pole on the battery to a relay and then to the horn button and horns. That way I could blow the horns without worrying about blowing a fuse from overdrawing the electrical system. The horn won't hurt the button itself - it's just a copper rod contacting a copper plate.

andy8190 · « **Reply #4 on:** February 24, 2009, 11:10:52 PM »

i didnt run any extra wire, just plugged the new horn into the existing horn terminals.

TwoTired · « **Reply #5 on:** February 25, 2009, 12:37:43 AM »

Does your new horn have a power or current used rating?

andy8190 · « **Reply #6 on:** February 25, 2009, 08:02:14 AM »

i will have to look on the package when i get home i work till 5 so check back about 6 and i will post an answer to that question

andy8190 · « **Reply #7 on:** February 25, 2009, 05:39:40 PM »

so i looked on the package the horn came in and the instructions and see nothing about the amp or volts it uses. its a fiamm horn i got from oreillys

TwoTired · « **Reply #8 on:** February 25, 2009, 06:34:59 PM »

Fiamms are usually much louder the stock and draw more current in the process.

I bought a set of dual Fiamms. They were rated for 115 db (or more). As, I wanted to see the cage drivers jump, and hit their heads on the their roof, when they tried to cut me off.

Anyway, the set included a relay meant to route power to the horns on a separate power lead, instead of through the horn button.

It depends on the current of the horn. The stock bike draws about 10-11 amps through the 15 A main fuse. If your horn adds 4 to 5 amps to that draw, the main fuse goes poof, and the bike rolls to a stop.

Were it me, I'd at least measure the current draw on your replacement horn, and then decide what the best way to power it is.

Your call.

andy8190 · « **Reply #9 on:** February 25, 2009, 06:42:34 PM »

so how do i measure that current draw because i dont want the main blowing and this thing is rated for 130 decibles?
and if i need to power it different how can i power it different but still use the stock button?

TwoTired · « **Reply #10 on:** February 25, 2009, 06:46:26 PM »

You'll need an ammeter connected in series with one of the connections to the horn. Connect to a battery and read the amps while the horn is connected. I'd probably use an ammeter capable of 10 amp throughput.

I'd recommend ear plugs to avoid hearing damage.

Cheers,

andy8190 · « **Reply #11 on:** February 25, 2009, 06:47:58 PM »

any suggestion on the second part of my previous post, i am guessing you didnt see it since i modified it later

mystic_1 · « **Reply #12 on:** February 25, 2009, 07:26:20 PM »

Run a dedicated, fused wire from the + battery post, through a relay, to the horn(s). Take the lead from the horn button and hook to the relay's coil. Thus, teh button trips the relay which powers the horn(s).

mystic_1

andy8190 · « **Reply #13 on:** February 25, 2009, 08:06:56 PM »

ok so i just went and got a relay and put it on. Now the only way i could get it to work was wire from the battery to the relay with a fuse inbetween. Now from the relay i put the black wire in the switch port and the green wire in the ground port and then run a wire to the horn from the horn port. Now what worries me is the only way it would work is if i splice a female connector with two wires. The female with two wires is on the ground port and one wire is the original light green wire and the other wire is the second wire going to the horn. Is this ok or will it fry the button also or is the black wire the only one to worry about?

did this even make sense?

andy8190 · « **Reply #14 on:** February 25, 2009, 08:58:13 PM »

ok lets try explaining this way...... i attached a wire from the battery to 30 with a fuse between the two. Now i attached the stock black wire to post 86, 87 has a wire that goes to the horn, and the stock green wire to post 85. There are two wires that are attached to the female plug that goes onto 85, one being the original light green wire and another wire that also runs to the horn because it has to prongs that have to have a wire, one for hot and one for ground. My question is will running the ground to the horn hurt the original horn button or is it ok?

TwoTired · « **Reply #15 on:** February 25, 2009, 09:31:51 PM »

I'll check the wire diagram if you say what bike you have. But, I'm thinking that most of the SOHC4 horn buttons provide a ground connection to the horn, not power. I don't know if your relay is polarity sensitive. But if it is, you need to put +12 power on the POS (post 86) relay post, and connect the horn button wire the GND (85) post.

Cheers,

andy8190 · « **Reply #16 on:** February 25, 2009, 09:33:29 PM »

i have a 1974 cb550, i mean the horn is working im just worrying about frying the button.

TwoTired · « **Reply #17 on:** February 25, 2009, 09:36:33 PM »

If the horn button is just powering the relay, there should be no problem. The horn button does provide a ground or connection to battery NEG for your bike.

Cheers,

andy8190 · « **Reply #18 on:** February 25, 2009, 09:41:06 PM »

so the button will be safe with the set up that i have?

TwoTired · « **Reply #19 on:** February 25, 2009, 09:54:08 PM »

I think you're golden!

andy8190 · « **Reply #20 on:** February 25, 2009, 09:58:02 PM »

good deal good deal, how that

isnt a "i hope im right" smile haha. My next project for safety measures is a brighter headlight, think i will go with the Sylvania SilverStar H6024 bulb first and then possibly relays after that (am i correct in thinking these bulbs fit right into the stock mount?)

78CB750CAFE · « **Reply #21 on:** February 26, 2009, 04:50:00 AM »

Quote from: andy8190 on February 25, 2009, 09:58:02 PM

good deal good deal, how that isnt a "i hope im right" smile haha. My next project for safety measures is a brighter headlight, think i will go with the Sylvania SilverStar H6024 bulb first and then possibly relays after that (am i correct in thinking these bulbs fit right into the stock mount?)

Yup, the H6024 will mount right in your headlight bucket. Now that you have a grip on doing the "relay thing" I suggest you do it for the headlight as well, one each for high and low beam. I am pleased with this same set up on my bike.

here is my relay install thread for reference:
http://forums.sohc4.net/index.php?topic=45894.0

TwoTired · « **Reply #22 on:** February 26, 2009, 11:19:03 AM »

The headlight relay mod is just a band aid, used to side step and hide faulty wiring harness connectors and switches. It only solves a small portion of the real problem

Check the voltage across the battery compared to the voltage at the headlight. The voltage disparity is what the harness terminals and switch are tossing into the air as heat, which is just wasted energy better used to keep the battery charged.

Improving the voltage to the headlight will certainly make it brighter, whatever headlight you have. The watt ratings for headlights are made at 12.8V. A 50 Watt bulb is only consuming 30 Watts if fed 10V, for example. A headlight intended to draw more watts, will make the voltage loss in faulty circuits worse, and it will never attain it's rated wattage or brightness expectation.

Worse, your 550 doesn't have a lot of alternator power to spare for more watts consumed by harness bits, switches and a headlight that consumes more power, particularly when compared to the 750.
The 550 alternator is rated for 150 watts at 5000 RPM, it only makes about 40-50 watts at idle (which is barely enough to light the headlight forget the about the coils, alternator and any other lighting loads the bike has). A stock bike with the headlight on, draws about 120-130 watts. Your battery depletes at idle with the stock components and will do so faster with a headlight that consumes more power. Further, the RPM point at which the battery begins to receive a charge gets higher, as it has to overcome the added headlight drain before it can charge the battery. And then, with engine revving, the power that would normally recharge the battery, is siphoned off to the headlight instead. The effect of which is that it is very hard to keep the battery in a well charged state, and the increase state level changes shorten battery life.

Finally, and few people seem to care about this, headlights don't throw a round light pattern. It's kind of sideways keyhole shaped. And, the reflector pattern for motorcycles is shaped differently than automotive light patterns so as to minimize light reaching oncoming drivers eyes. There are many who simply don't care about other drivers ability to see on a dark night, and are unconcerned about anything other than themselves and what "looks" good to them. However, I do question the "wisdom" of making oncoming vehicle drivers blind. But, for some, making other people pay for your life decisions is what makes living worthwhile, I imagine.

Do the voltage loss test first and correct that problem, if found. You might find out that your "weak" headlight works pretty good when fed its rated voltage (or above, if the battery is being charged nearer to 14.5V).

Cheers,

andy8190 · « **Reply #23 on:** February 26, 2009, 11:29:19 AM »

so i need to get a voltmeter and check the power at the battery terminals and then the wires that feed the headlight, or an ammeter?

mystic_1 · « **Reply #24 on:** February 26, 2009, 12:25:14 PM »

Voltmeter.

Don't confuse the two, they are different animals and trying to use an ammeter as you would a voltmeter causes Bad Things.

mystic_1

andy8190 · « **Reply #25 on:** February 26, 2009, 12:56:42 PM »

ok so what should the reading at the terminl end of the headlight wires be?

Patrick · « **Reply #26 on:** February 26, 2009, 01:46:43 PM »

On a perfect electrical system it would be the same as the reading at the battery. You probably are going to lose a few tenths, though.

78CB750CAFE · « **Reply #27 on:** February 26, 2009, 02:21:30 PM »

Quote from: TwoTired on February 26, 2009, 11:19:03 AM

The headlight relay mod is just a band aid, used to side step and hide faulty wiring harness connectors and switches. It only solves a small portion of the real problem

Well I disagree a bit with that, though I know you know far more than I do regarding m/c electrical systems ...
From what I understand it also lightens the load on your expensive and hard to find (for some models) switches. Also,running heavier gauge wire for the power to your headlights and or horn and relays allows you to pull more voltage for higher powered aftermarket items safely. Sure it is not a replacement for having a properly functioning wiring harness, but it helps in this instance even if you do.

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Author Topic: question about a new horn (update....put on relay) (Read 3059 times)