Weak Air Horns

[jabster]

Hi.

So I've had air horns on the bike for a number of years now. I have the cheap Autozone ones, one mounted to each exhaust hanger with a custom bracket. The compressor is under the right side cover. Bought the horns back in 1999 or so; bike was sitting for close to 10 years before last summer tho. I am not using the cheap-ass relay that came with the horns; I replaced that less than a year after I bought the horns and they went off when I was cruising down the highway. Scared the crap out of me.

They've been fine since then, but last fall, and confirmed this winter, they no longer blast immediately when I press the horn button.

If I hold the button, they do build to the correct volume tho. Same thing happens when I connect it directly to the batter (bypassing the relay): Whimpering, gradually building to full volume. Takes maybe two seconds to get to full volume. Which doesn't seem that long until you need the horn right NOW.

I've also tried another compressor, and the same thing happens.

All the hoses appear to be on tight.

Would a small leak cause that? I'm leaning against a leak because I'm getting full volume eventually.

Do air horns wear out? Or, more appropriately, how long do they typically last? Should I just go back to Autozone and replace everything?

Any other ideas or things to check?

Thanks,
John

[old2soon]

Crud build up in the horn itself. That is the reason big trucks have covers over the horn opening. And i have NO idea how YOU would go about cleaning them IF that is the problem. RIDE SAFE.

[Tx Bohemian]

When you say tried another compressor was it like a shop compressor or another one from another bike you plugged in to replace the original?

I've had a similar situation but my horns wouldn't work at all. It turned out to be a bad ground and the compressor wouldn't spin fast enough to blow the horns.
Weird thing about the ground is it worked since I got the bike 2-3 yrs ago and all of a sudden it seems the bolt lost all grounding capacity. The ground wire was good cause I could jumper it directly to the battery and it worked, so I repositioned the wire under the bolt and even jumpered it directly to the head of the bolt and nothing!!
I ended up using another bolt for the ground.

[BlueValk]

Hi.

 I replaced that less than a year after I bought the horns and they went off when I was cruising down the highway. Scared the crap out of me.

Thanks,
John

That's funny!  Mine did the same thing.  Kind of embarrassing going down the road with your horns on full.

Try spraying some WD-40 into the back of the horns themselves.  Then if you can, blast some air from an air compressor through them (20psi is a bunch).  Or just use the horn's compressor, it should work.

Mine are 12 years old, and need an occasional blast through them.  Also, add a couple of drops to your compressor once in a while.

My final fix was to set up an air storage for the horns.  It is somewhat involved, so I won't go into it here.  But, that is a sure way to have a truly instant air horn.

BlueValk

[F6Dave]

My Stebel horns did that.  Who knows how much corrosion is in the compressor as it takes in water and other road crud.  I sprayed a lot of lube in the intake while operating the horn, and that fixed the problem.

[jabster]

I replaced that less than a year after I bought the horns and they went off when I was cruising down the highway. Scared the crap out of me.

Thanks,
John

That's funny!  Mine did the same thing.  Kind of embarrassing going down the road with your horns on full.

Fortunately mine only did a couple of intermittent blasts at me. Had to ride the last 50 or so miles hornless tho, as I stopped and disconnected them.

I guess I'll try blasting some WD40 into them before doing anything else. Then if that doesn't work I'll just buy new ones. They aren't that expensive. If that does fix it I guess I'll put a screen over the horns or something to at least try and minimize more crud getting in there.

And the second compressor referenced above was an unused horn compressor. Not really sure how I got two of them. Maybe the horns came with two? I don't remember to be honest, but they're identical so maybe that was it.

My final fix was to set up an air storage for the horns.  It is somewhat involved, so I won't go into it here.  But, that is a sure way to have a truly instant air horn.

Got it. Compressor keeps a reserve tank full, and the button releases a valve on the tank, right? Probably more than I really want to do tho.

 Tx Bohemian:
I'll look into the ground as well, but I'm eventually getting full volume out of the compressor. I'm getting full power, it's just taking awhile.

Thanks,
-John

[MarkT]

Two problems here.

1.  You have a reed horn.  They get deposits on the reeds and that affects their response and tone.  You need a diaphram horn to eliminate needing to "clear the throat" of the horn.  Diaphram horns use a different method and are self-cleaning.  In fact, no amount of crud will stop them from blowing.

2.  You are using a vane compressor that generates a high volume of air at low pressure on the fly.  If you want a truly loud and reliable horn, you need a piston compressor, a storage tank, and a solenoid that unleashes the already-generated and stored energy.  That is why air tank horns are so loud - the air is stored up over time and released all at once.  Mine has 135# of pressure and is truly a Fire Truck horn.  

Here's a shot of the horn, the compressor with solenoid (behind the manifold), and the tank. Note the pressure switch, gauge, schrader valve (for air hose for tires, or pre-charging the tank with external air to preserve the compressor) and output to the suspension off the manifold. The air system is by Hadley.  The horn by Grover - who also makes train horns.  It's a little effort to set up, but worth it in my opinion.  You can also fill tires, and have an air system for the suspension (which I also set up).

BTW, Motorcycle Cruiser featured my horn in Nov 2003.

The horn at http://www.horseapple.com/Valkyrie/Tech_Tips/Train-Horn/train-horn.html

The air system at http://www.horseapple.com/Valkyrie/Tech_Tips/A_Premium_Air_System/a_premium_air_system.html