Modern Vespa

So i re-wired my 2 74 US Rallys so they would be batteryless. One of them is 12V AC, the other is 6V AC. I'm running them without horns right now but for safety reasons I want to have anything, even if it sounds like a duck.

Does anyone know of an AC horn that fits a US Rally horncast? I found AC horns for smallframes on scooterwest but does anyone know of a large 3" AC horn sold elsewhere?

I was thinking if there isn't a horn that works, i'd buy a small frame horn and build some mounting bracket for it to fit the 3" hole, and find a chrome cover to hide the smaller horn. It'd be a pain, but I don't know of anything else.

I know I could add a rectifier just for DC for the horn but I already installed the harness and don't want to tear about the harness or re-wire it again.

Thanks

Same problem here. Have you thought of taking your old one apart?

Recent thread on this.. You could: A. fix the old one if you're lucky or B. make a custom horn with a scooterwest guts and original front. Ok, it's a bodge, but if well done, no one will ever know.

If you could find a DC horn to fit, might work with a small full wave rectifier just on the horn circuit?

Good luck, please keep us posted so I'll know what to do.

Have you tried a Lambretta horn? There were many DC models if I recall. My expertise on this non-existent because I only seem to ever remove horns while I never install them.

I have a giant bag of horns. And I am not joking.

The two DC horns I have work fine so I dont need to work on them. I was just hoping to find two AC horns but I guess that doesn't really exist.

I'll swing by Radio Shack first thing in the morning to see about finding a real small rectifiers for the horn circuit. Hopefully there's something small I can hide in the horn cast.

My Lammy is missing the horn right now. When i finish the Rally's I'll start working on that.

Thanks

Right behind the horn will be easy & no harness cutting if it fits. Four diodes in shrink wrap should be compact & wont short out. Where's the popcorn...

thanks

Beedspeed sells a 6V large Rally Horn. It will also work on a 12v system either ac or dc. ^8 Pounds is pricey but you wont have to f*** with anything and it will fit. Shit order some bling from while your at it.......JMO

Check moped places as well.

Many mopeds ran the 3" ac horn.

iirc my two Motobecans had what seems like a big horn.

It's listed @$106.32. Interesting what they say about what voltage it will work with: ScootWest DOES have 6V DC Rally horns also, but this one @$129.95

I use a normal small 12v ac horn on my Rally.
I removed the front stainless grill from a standard large Rally horn & use it to cover the small horn which i have tucked inside the horn housing.
I also painted the smaller horn black so you cant see it.

Ok so here's what I've gotten so far:

I've managed to find a bridge rectifier that's small and compact at Radio Shack. I hooked it up and measured DC voltage and amps on it.

On my 6 volt Rally measured with a multimeter

DC Amperage DC volts Condition
.3 1.6 Idle/ no button pushed
1.1 5.05 Idle/ horn button pushed
1.6 5.5 Rev'd/ button pushed

12 volt Rally

DC Amperage DC volts Condition
.3 1.3 Idle/ no button pushed
1.0 5.3 volts Idle/ horn pushed
3.47 12 volts Rev'd/ button pushed

I hooked up the 12V horn and rev'd the shit out of the engine. I could still barely hear any noise.

I hooked the 12V horn up to a battery and it was loud and constant. It measured 11.24 volts DC, 3 amps DC.

Anyone know why it's not properly working?

Malcolm, you have a strong headlite, right?

I wonder how your horn sounds connected to that circuit with the lite disconnected?

I'm thinking maybe just one of those stator windings is going bad on you & this might tell you if that's the case.