guyenoir

My old horn fell off after my Rebel was towed (I parked where I shouldn't have). I bought a 2-tone Hella Trumpet horn online (because the only motorcycle repair place in Manhattan didn't have any horns in stock), and now I'm worried it might draw too much power for the bike to handle.

Amazon.com: Hella 007424801 Twin Trumpet High/Low Tone 12V Horn Kit with Bracket: Automotive

I'm mainly worried because the horns came with a 30A relay but according to the service manual the bike only outputs 20A. Are these horns going to blow a fuse or drain my battery? Do I need a wiring harness, and if so, what kind (are there different kinds)? Suppose I only use one of the horns, will that make a difference? Do I even need the relay?

I realize some of these questions may be kinda stupid, but I don't want to mess with electrics without knowing what I'm doing, and these horns didn't come with instructions.

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flitecontrol

The towing company is responsible for any damage they caused to your bike.

If you like, you can install just one horn using the bike's existing wiring. However, the stock wiring probably isn't robust enough to supply all the juice the horn can handle - see below for explanation. But my suggestion is that you use both because you will be heard far better than the stock horn, which is rather puny. This shows you how to wire it: Wiring a Relay for Accessories

There are prewired kits available, but as you would expect, they are more expensive than buying the supplies and making a custom set. Wiring the power directly to the battery with larger diameter wire (say 14 gauge) will give maximum power to the horns and result in maximum volume. Because the horn is used sparingly, the drain on the battery will be short term, and it won't hurt the battery.

Don't worry about amperage size of the relay. They simply provided one that will be more than large enough to handle the load. Better that than one too small. As stated in the instructions for wiring a relay, add an inline fuse holder (available at Radio Shack, WalMart, auto parts, etc.) and use a 20 amp fuse.

Hope this helps.

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I'm keepin' all the left over parts. I'm gonna use 'em to build another bike!

2001 Rebel 250, 1989 Vulcan 750
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Twister

No such thing as a stupid question. Stupid would be not to ask a question and remain ignorant.
Who needs the instructions when you have such a nice group of people in this forum.
I did use the extra relay that came with the horns.

Connect your cables (if I remember correctly are green) the ones that were connected to the horn directly to the relay.
Even better take pictures of what you got and gives us a list of the numbers on the spades of your relay and we will walk you thru it.

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Every ride is a joyride on a Rebel

1986 CMX250C "Miss Triplehorn" 17K miles
1984 GL1200A 106K miles