davidmasse wrote:
The sound it made may have been more of a whirring than a sputter. With the FF on, the motor idling, a car behind me, and the echo from the garage entrance, plus my 55+ hearing, it's hard to be more precise.
Water can't be an issue, unless condensation needed to be factored in. Haven't washed the Vespa, and there's been no rain. I did ride through a patch of wet pavement this morning but there was no actual water on the ground or spray. Besides it worked normally just a few minutes earlier.
I should be able to test the horn with my 12 volt car battery charger. I'd be very happy to find a faulty connection since that's easy to fix. My concern is that I installed the horn specifically for the safety aspect. If it turns out to be unreliable, it completely defeats the purpose.
The horn is wired as suggested on MV: direct positive and negative lines from the battery, fuse on the positive line at the battery, relay on the positive line to the horn (terminals 30 and 87) with the relay coil connected to the original Vespa horn terminal wires (i.e. those spade connectors were the ones directly connected to the OEM Vespa horn and they're now connected to terminals 85 and 86 of the horn relay).
I'll try again at lunch time and see what I get.
Otherwise I'll be looking for recommendations for other loud horns.
You are getting a sound so power must be reaching the horn. If it was working fine before, then you must have installed it properly at the outset.
Some people had separated their Stebel and used aquarium tubing as an air line from the compressor to the horn. If something like that failed, I imagine that you could see a reduction in sound.
Testing the horn directly from a 12v source is a good way to see if the problem is in the wiring, or the horn itself. It could be both (unlikely, but possible), but at least you will know if the horn works.
It looks like this will be a process of elimination.
For what it is worth, comments about the Stebel horn failing comes up when you google search the topic. Keep in mind, that a lot of time, the horn is exposed to the elements. As louisq has pointed out, we don't see many reports of the Stebel failing after installation on a Vespa. I have always attributed that to the fact that they are well protected from the elements when placed in the legshield.
If you figure out what the problem is, please post it so that we can help others out in the future.