LCGB Forums

How does this simple conversion work
lambretta 12v conversion uses the brown lighting circuit through a PX regulator, not sure what the regulator actually does, can anyone enlighten me.
The reason I'm asking is Im converting back to a 6v 6pole AC system and looking to get the best out of what I have and the scoot is fitted with an electronic wiring loom so only one supply wire.
The pink and purple coils aren't used in the conversion, does anyone know why ?

Looking at the wiring diagram in sticky's book
Coil 2 & 5 are wired as a pair (Pink)
Coil 1 (brown ) is a stand alone supply
Coil 4 (purple) Is a stand alone supply
It seems that 3 of 4 coils available arent used and this seems such a waste

The regulator limits the voltage produced by the power generation coils to 12v in the case of a 12v regulator or 6v in the case of a 6v regulator. This is to stop you blowing bulbs etc....

I would be more inclined to be looking at what systems you have in place, and what you need to get to have it operating properly...

i.e. is this a 6v 6pole stator, and if so how should it be wired.

It also sounds like you have a simplified loom with just a "brown" feed from the regulator to the rest of the scoot?

I am refitting the original LI crank and hence the 6v 6 pole stator and flywheel. The wiring loom in the scoot was changed for a single wire feed system as I had upgraded to an electronic ignition system.
I am trying to work out the best way to return the scoot to 6v electrics without having to rewire the electrical system & interfering with the bodywork too much, the LCGB workshop easy 12v lighting fits the bill perfectly as it only uses one feed wire for all of the electrical system,( same as the electronic ignition I took off)

The LCGB workshop system stated that its "A very simple modification you can carry out to improve the lighting on your 6V Lambretta, is to use a new regulator to convert the flywheel output to 12v"

The regulator I have with my electronic kit just dumps the excess power to chassis to maintain 12v ( not much more than the old Zener diode clamp) I was wondering if there is a little transformer / regulator circuit in the vespa system to make it boost the output to 12v?

Meds wrote: I was wondering if there is a little transformer / regulator circuit in the vespa system to make it boost the output to 12v?

You really cant make 12v from something that has windings to make 6volts. You would need to add a step up transformer to convert 6v AC to 12v AC and then regulate it.

I agree but the easy 12v lighting from the LCGB workshop suggest otherwise and I'm struggling to work out how it's done.

Why don't you just buy an Li electronic flywheel to match your Li crank? It would be a straight swap, though you would need to check the timing once fitted.

All the advantages of the electronic ignition and 12v lighting without the hassle of having to understand electricity.

Why don't you just buy an Li electronic flywheel to match your Li crank? It would be a straight swap, though you would need to check the timing once fitted.

All the advantages of the electronic ignition and 12v lighting without the hassle of having to understand electricity.

Gotta agree with knowledge.I cant understand why people choose to run Lambrettas on ancient points and condensers nowadays as a modern 12v electronic kits not seen under the cowling,has brighter safer lighting and doesnt require changing and fiddling like points when they burn out!

The reason I don't want to buy an electronic kit is it's a spare engine and wouldn't be nearly as much fun.
No worries though, I will get it running, scope the stator output and sort out accordingly.

foremanbob wrote:You really cant make 12v from something that has windings to make 6volts. You would need to add a step up transformer to convert 6v AC to 12v AC and then regulate it.

Not exactly true, because the two 6v lighting coils joined in series produce much higher voltages than you might think, if you measured a 6volt stator you would see the voltage produced at the stators brown wire is in excess of 6v ac.
The 12v regulator will work although the wattage will be lower than a full 12v stator conversion.

The 6v to 12v easy upgrade works on just one wire to feed all electrics.
I built a loom for my cutdown with just the one wire coming from the regulator ran that up to my handlebars and the splitthe wire to feed horn,brake,and lights.
Followed the wiring instructions from the mag to regulator given on the workshop page.
Have no idea how it works but it does,thats all that matters to me.

A couple of people have sung the praises of a decent points set up and since you've decided to revert to that system I can vouch for its efficacy. When I got my present scoot it came with the flywheel in two pieces (4 pole), so I've since changed to 6 pole but I've found that this seems more susceptible to minute changes in the points and plug gaps than previous 4 pole systems I've run. It's imperative to keep an eye on the points and plug gaps - one thing I found to clean the points is a metal nail file, and the plug gets cleaned with a soft wire brush meant for suede boots. Starts first or second kick every time, and it's nearly 55 years old!

Thanks for the help guys,
I'm back on points now and it's starting fine and running fine.
I did some very basic checks on the electrics and found that there is less than 1v difference between the brown and pink wires (they are pretty much in phase)
The lights operate from either the brown the pink or both
Both are giving no load outputs of approx 10v
So I'm going to connect brown and pink together and run them through the regulator and see what happens.
The worst is I set up some circulating currents through the coil windings and melt them, at best I will have decent lighting.
There is nothing like playing around to see what happens.

Well I tried the following.
Brown stator wire through the regulator supplying all the electrics, works ok, put the back brake on and the headlight dips noticeably.
Pink stator wire through the regulator supplying all the electrics, works ok, put the back brake on and headlight dips noticeably but not as bad as the brown.
Pink and Brown Stator wires connected together supplying all the electrics through the regulator and it works much better than the single feed, put the back brake on and the headlight dips a bit but no where near as bad as the single feed system
So far it's a result, just not sure of the long term effects on the stator coils.
If anybody has tried this let me know of the long term effects.
Thanks for the tip Captain Pugwash.

Meds wrote:Well I tried the following.
Brown stator wire through the regulator supplying all the electrics, works ok, put the back brake on and the headlight dips noticeably.
Pink stator wire through the regulator supplying all the electrics, works ok, put the back brake on and headlight dips noticeably but not as bad as the brown.
Pink and Brown Stator wires connected together supplying all the electrics through the regulator and it works much better than the single feed, put the back brake on and the headlight dips a bit but no where near as bad as the single feed system
So far it's a result, just not sure of the long term effects on the stator coils.
If anybody has tried this let me know of the long term effects.
Thanks for the tip Captain Pugwash.

Your welcome,
I think it's Best with both the pink and brown wires connected, I can't see any real long term effects so long as the stator and flywheel are in good condition.

dimming headlight - use led rear bulb.

I have done the easy 12v thingy. Used an led to stop the dimming headlight, since then have butchered the backend of loom and run brake light and horn off an added battery. So now brake light is really decent and has no effect whatsoever on headlight. Fitted a rectifier (maplins or vehiclewiringproducts.co.uk) and wired it so as to trickle the battery but not sure how effective it is to be honest.
This was covered in depth on old forum by I can't remember who unfortunately. Have also setup a swappable arrangement where I can run all lights and horn from the battery should the fancy take me just by swapping a plug around. I should've drawn it up as if I were to look at it now I'd have to trace everything back again to remember

I love the points setup.

Nigel
Have you used pink and brown or just the brown as the feed?
What LED light did you use, a full light backplate or just a lamp.
I was considering using just the lamp as my rear light is a carello.

Nigel. S wrote:
I love the points setup.

I agree with you, a decent points setup is a very good system.

Much better when they are fully 12 volt dc converted

Have also carried out simple 12 volt conversion and used a Maplins bridge rectifier to charge a 7Amp hr Alarm type battery. I have then fed the brake light and a DC horn from the battery. Great brake light and a super horn sound.

I am about to convert a second scooter to the same configuration for a cost of a few quid (Battery £15/ Rectifier £3/ DC Motor cycle horn £8 and a few meters of wire.
Jono

Hi
bulb type as mine is carello too. Gave it a good polish up with some autosol first.
I just used brown. Can't think why using two would be a problem. Sounds like Jono has same setup as me.

Well the system seems to be working well other than the dimming of the head light under braking,
I have cured that with an LED tail lamp (running on AC) but the traditional lamp seem to give off better light.
Im hoping I can improve the the light issue that with a better LED tail lamp.
Any advice on LED tail lamps would be helpfull