Scooterotica

when i press my horn with the lights on the front light dims to almost nothing and the back light goes out . i fitted a brand new 12v stator and cdi but not a regulator could the old regulator be faulty or is this a common problem also do i need a side light for an mot as i have only got hi and low beam. thanks

Sounds like a short circuit in the horn/light switch................

a new switch before a new regulator then ?

most lambrettas without a battery do that trick...
before buying a new switch;

check the exsisting one is working properly using a multimeter
[the only wire that should earth is the white one when you press the horn button]
the lights are likely to go out completely if the switch was earthing incorrectly.

see what happens when you sound the horn without using the switch, so earth the side of the horn where that white goes to. chances are your lights will dim...
was this a problem before the new stator ? the CDI is nothing to do with it.

find a sympathetic mot tester
if you mean the festoon, you shouldn't need it for an mot

Whilst we're on this subject, my latest TV175 has a similar "problem", although my lights hardly dim but the horn, whilst loud, sounds awful.

The bike has a 12v Electronic kit on it (no battery) and I have no other electrical probs at all.

I'm thinking that the horn may be the original one which used to be powered by the battery, and is now being powered directly by the electronic system. Could this be so?

Also, would an original battery powered horn be AC or DC?

What sort of horn should I have for the electronic set up? AC or DC?

Sorry but I'm a complete numpty when it comes to the electrics side of Lambrettas (not too hot on the rest either....). I never paid attention in Physics at school.

Chris

The original TV175 horn would be a 6V DC type. The ideal one for electronic non battery would be a 12V AC type, but it will still, probably, sound awful.

It really is worth fitting a battery to run your horn and rear brake light, leaving the stator to run all other electrics. You can get a fairly small sealed gel type from RS or elsewhere, that can be fitted inside toolbox that doesn't take up much room. You'd need a regulator with the extra connection to charge the battery of course, and would need to change the horn to a DC one. But you would end up with a very loud horn instead of a duck fart and a good bright rear brake light and no dimming of other lights.

dapper wrote:It really is worth fitting a battery to run your horn and rear brake light, leaving the stator to run all other electrics. You can get a fairly small sealed gel type from RS or elsewhere, that can be fitted inside toolbox that doesn't take up much room. You'd need a regulator with the extra connection to charge the battery of course, and would need to change the horn to a DC one. But you would end up with a very loud horn instead of a duck fart and a good bright rear brake light and no dimming of other lights.

This sounds like what i need can you advise as to what amp battery will be needed for this
Cheers Al

I've got a Yuasa NP 1-2-12 12Volt 1.2 Ah, about the size of a fag packet mounted in my toolbox. LED rear lamp, normal headlight lamp, all bright as feck. Horn and brake light work even with engine off

dapper wrote: 1.2 Ah

it's good you only need that rating, keeps the physical size small. i was surprised to learn the other day that oe batteries were something like 11Ah! what wattage are your headlamp bulbs ?