1980 vespa 12v or 6v? Brake light mysteries!

Hello,

1980 Vespa Si. I thought it was a 6V. All the original bulbs are 6V, but blown. I did a test with a multimeter and it said 8-10V at idle and 12-14V when running. Wierd!

Also, how do the brake lights work, they always have voltage running to them!

Re: 1980 vespa 12v or 6v? Brake light mysteries!

Leon Swarmer /

Can't tell you what the voltage is supposed to be,

There should be two wires going to the rear light. The tail light (which should be hot any time the engine is running) and

the brake light which should only be hot when a brake lever is being pulled. If they are both hot all the time, then look for a broken brake light switch. Or some other strange wiring set up.

Leon

Re: 1980 vespa 12v or 6v? Brake light mysteries!

Ok, I think it is 12 Volt. I put a brand new 6V bulb in the tail light and it was very bright at idle, and when I rode off it burnt out.

The tailight is actually controlled by a switch I have on my headlight.

I checked both brake levers and they both seem to be working (they break the circuit when pulled). It seems that there is supposed to always be voltage to the brake light, just more amps go through when the brake lever is pulled. Is that what the reisistor is for?

Re: 1980 vespa 12v or 6v? Brake light mysteries!

Try an 1157 bulb in the rear. I also run a 12 volt headlamp with no problems.

Re: 1980 vespa 12v or 6v? Brake light mysteries!

Ok, the original bulb said 1157, but I have no idea how to search it. I bought some 12V bulbs from Murrays that looked similar, I hope these work!

Re: 1980 vespa 12v or 6v? Brake light mysteries!

Leon Swarmer /

1157 is 12 volt

Re: 1980 vespa 12v or 6v? Brake light mysteries!

1157 is a common automotive tail/stop(two filament) light, yes, 12 volt.

Re: 1980 vespa 12v or 6v? Brake light mysteries!

Ok, thanks guys it's 12 Volt.

Could someone please explain how the brake lights are supposed to work? It seems the levers are grounded, but when they are pulled the ground is gone so current gos through the bulb.

right now there is always ~12V at the rear stop bulb but the bulb is very dim.

Re: 1980 vespa 12v or 6v? Brake light mysteries!

I think you did a good job of explaining it...There are contacts under your brake levers. When you pull them, they separate and the brake light is energized.

The running light will be dimmer than the brake light , esp when idling. When at speed, it will get more current and be brighter.

The brightness of the brake element should exceed the running light, which makes sense, as you want it to be seen.

I think with the proper 6v bulb the running light may be stronger at idle, but it is more convenient getting the 1157 bulb.

Re: 1980 vespa 12v or 6v? Brake light mysteries!

1154 is a 6v version of the 1157, but go for the one that works for you.

as a "safety feature" the bike's engine is grounded either thru the taillight or the handlebar brake switch.

If your stop light blows, and you pull the brake it should kill the engine.

It sounds like you have it connected correctly, even if it seems wrong.

Re: 1980 vespa 12v or 6v? Brake light mysteries!

I have tried the 1154 bulbs, but they engine always cuts out at idle. Using the 1157 bulbs, it stays running. This would be with my Grandes.

Re: 1980 vespa 12v or 6v? Brake light mysteries!

OK,

The rear stop light is an 1156 right now. For some reason, it always lightly glows whether the brake levers are being pulled or not. I have no idea how this is possible unless it is the wrong bulb.

Is it the wrong bulb? Should it glow when the brake levers aren't pulled?

Re: 1980 vespa 12v or 6v? Brake light mysteries!

Hahaha, ok again. The brake light works now! However, it is very slow to react and not that bright, though it would be easier to se at night.

The 12V rear bulb blew out. I don't know what's going on with that. I don't have a front light installed yet, so maybe that's the issue.

Re: 1980 vespa 12v or 6v? Brake light mysteries!

Isnt the 1156 a single filament bulb? You need the 1157 which has the dual filament. Each circuit needs a filament, ie, the brake light filament is separate from the running light filament. Also, on the contact end of the bulb, you will see two contacts instead of the one contact I think the 1156 bulb has.

Re: 1980 vespa 12v or 6v? Brake light mysteries!

yeah 1156 is a one contact.

There are also other bulbs out there with two contacts and one filament- you want to avoid those too.

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