Modern Vespa

Guys,

This is driving me mad, mad I say!

OK, I had 10 minutes to kill, so I thought I'd go fix up the switch cover and horn which was showing light surface rust on the chrome.

The 10 minute job turned out to be a nightmare and I still can't get the horn working right. It beeps non stop as soon as I start her up. Pressing the button stops it from beeping, the moment I let go it goes non stop. And all I did was take off the covers to polish and wax then replaced. I didn't touch anything else at all! Honest.

If I'm not mistaken, the horn button is just to break contact. It normally should be in closed position, ie: grounded. So wtf happened? Why did the circuit get reversed? Or am I missing something here? It's late and I'm getting stupid, so there must be an easy explanation and fix, right? Help me out please.

it all depends if you have a battery setup or not, whether the horn is normally on or normally off ( whether the button breaks or makes contact )

Hey Eric!

Non-battery setup, I had a look and the horn button is in closed (breaks contact) position.

I don't understand what happened, all I did was unscrewed 3 screws from the horn, unclipped 2 wires, polished the horn and put it back together.

So I'm still scratching my head over this.

The horn button is normally on (pressing button breaks contact), worked as it should all this while until I took the horn off and put it back. I did not do anything other than that.

Now it beeps non-stop till I press the button and it stops beeping until I let go, ergo somehow things got reversed.

An easy fix would be to bodge the button contacts and reverse it. But I can't for the life of me figure out what happened and I know it's gonna bug me till I find out. Any ideas?

are you sure you put the ground wire back into the proper contact point?

are screws breaking the wiring maybe

I was careful, and I did check that the 2 crimp connectors slotted back to their original positions on the horn. I even checked a wiring diagram, green and white, left and right.

I did try reversing the wires into horn, no difference. Should there be?

The way the horn fits into the horncast, the 3 screws just screws the horn in place, not touching the wiring at all.

It really shouldn't be anything to do with the switch button, nothing was touched there. It's just your basic horn/light switch with a 'normally on' horn button.

I nicked this pic;

is this on the et3?

if so,i will go take out my horn and put it in and see if i notice something.

it may sound silly,but you know when you drop something small on the ground and you can't find it you drop a similiar item on purpose to see if it helps.

sounds retarted,but i can do it easy breezy

Mucho gracias Jimmy!

Hope them gremlins are not over at your place too.

Here's what I did, I took my switch cover off and then put it back. Then I took the horn off by unscrewing the 3 screws and the 2 crimped connectors, then put them back. That's all I did. Now the beep's reversed. Fek.

I'm not sure if the DC horns are polar or not.

Have you tried reversing the plugs on the horn?

( i don't think they are ....as horns are a lot like light bulbs... but it's worth a try )

after you try switching wires,when you removed the swith cover you may have loosend a wire back there.

on my et3 the wires are sensitive and are held in by little brass screws(don't drop one,you will never find it)that clamp down on the wire.re-check that completely.

stop cleaning the bike

you know how we are about shiny bits here

Eric, yep, did try reversing plugs and didn't make a difference. It just kept beeping. AC horn. All I did was prise the switch cover off and put it back on. I will triple check just to be sure. I hope I don't sneeze while doing it, I don't know what else may fek up. I mean, talk about touchy Vespas, this boggles the mind.

Haha rust removal != cleaning!

OK, prised open the switch cover and took off the one screw holding the switch plate on. Double checked all wires and they are all in place held tight by the little brass grub screws. Clean, no corrosiion, no loose ends, nothing. The horn button contacts are working as they should, ie: connected normally and disconnected when the button is pressed.

Double checked again the 2 wires connecting the horn and they are snug in place and in the correct positions. Swapped them over just to check but it's still the same. The horn just keeps beeping until I press the horn button. WTF!

Just to add, everything else works - lights, high/low beam etc., just the fekking horn.

Try loosening the screws just a little. Sometimes on real little tightly packed devices you can get a short circuit by cramping something with too much tension on a screw. Or if the screws came out completely swapped the long one with the short one?

heres what im thinking

is it possible to reverse the polarities on a non battery setup?
if so i think thats what youve done....... maybe

to change the polarities touch a screwdriver from the positev to the negative two times(short it out)twice or is that three times anyway you can google it

last time i changed polarities was a while back on a morris major cause the little beast was positive earth- to run a modern radio in it required negative earth

i would suggest you look into that for youself though as im a bit rusty on the process

This would be a BAD IDEA.

The whole touching grounds thing is to set the polarity in a regulated DC generator-type system.
It will not work in a Vespa's unregulated AC alternator-type system.
And it might cause SOMETHING BAD to happen.

I don't know these models well enough to make an intelligent positive contribution to this discussion, but I can say that this is NOT a polarity issue.



- Eric

thanks eric sounds like i almost made it worse
i didnt know it wont work on an ac

hang on isnt the horn dc or is that just on battery bikes

yes

just batt bikes

Josh -

Yeah. Polarizing the regulator is a weird old-style generator-with-mechanical-regulator thing.
I forget exactly what it does, but I believe it magnetizes a relay in the regulator in the proper orientation. Outside of that very specific type of system, it isn't necessary.

- Eric

there are some possibility
sort wires on switch or on horn section, could be the wires touching the frame/fork... bale with seal tape
worn switch, there is a spring... could be not back on first position when you press the button or worn switch (short circuit) itself
find SIEM switch... the cover made from brass, so you don't need clean the rust
all but OG made from brass... here's just sample

that is a beautifull pic of a horn nino



senkun,are you running a stock et3 pipe on your bike or do you have aftermarket.

sorry to change the subject

it was gettin a little horny

Reverse the polarity, huh? I think we have a job for you on the starship Enterprise!

yes where would we be without polarities siging hymns in a mormon church perhaps lol

pity have been opened to make it work
hey Senkun how about your P90?

Thanks for more insights guys.

This reverse polarity thing is intriguing, I had no idea.

To be honest, I have not really looked at how the electrics are set up on my ET3, guess now is the time to figure it out. It looks stock, with the CDI unit in the left cowl compartment. Not the real deal Ducati but looks just the same.

The only changes I see are the addition of an indicator relay (scoot has indicator lights) and a regulator of some sort. I posted this pic before.

Now does this mean that somehow this is a regulated AC system?

hey Jimmy, nope not stock. It's some old Sito sport exhaust that looks like the regular box style but came bright red. I matted black the fekker!

yo Nino, yeah the switch looks like a brand new repop but horn is a nice original (it was a bit tarnished not rusted) looks good as new now - see below

The P90 I got it running now but haven't done much to it since, everytime I felt like doing some stuff I seem to find myself takin the ET3 for a ride instead haaha

Now back to the horny business.

In answer to my own question re: the regulator.

I tried to trace where the green wire goes, but it disappeared into the murky depths within the frame amid a tangle of electrician's tape. My nasty suspicion is that the wiring had been bodged by the previous owner.

I haven't untangled the mess yet. As it is, I don't think the regulator does anything, I mean, look at the pic - one green wire to the regulator and one black to ground. There should be 3 connections ie: input/output/ground. Amirite?

Okay, I know you're probably saying the same thing, but this makes absolutely no sense.

I took a little Electrical in college, so let me see if I can think this through.

Normally, in your set up, current goes round the circuit through the button. Pushing the button breaks the circuit at that point, moving current to the horn instead (or something like that. I'm missing details, and trying to simply at the same time. It's been awhile). If there's a short somewhere, that would mean the current going to the button is shut off, so juice is running to the horn. But why in the hades would pushing the button shut the blasted thing off? Sounds like you've really gotten yourself crossed up with this one. That, or I've forgotten more of that class than I thought, and none of that made any sense.

The only real help I can offer break out the voltmeter (cheap if you don't have one, but borrow it if you don't think you'll need it again) and go to town testing where juice is and isn't flowing.

However, if the previous owner has a homemade wiring harness or some other silliness in that rat's nest of tape and wire, you may end up taking the thing apart. Quick fix? Take out the horn.