Modern Vespa

Does anyone have a decent wiring diagram for the smallstate (no yellow wire in the junction box) that also details the switch? What's in the manuals is essentially useless. TIA.

What's the problem? The switch is different only because there's no "parking light" position. Are you trying to use a regular "VBB" switch?

Since the stator has no yellow for the "parking" lights they get fed from the white wire at the switch iirc. Also, the load requirement is a little different with there not being a front park lamp, plus the brake lamp is 18w instead of 10w. This applies to the VA15T/VNB6 and the Sears Sprint as well. Plus some 1966/1967 U.S. Market Vespas. Basically if it's got a MM taillight it's this exact wiring.

No, I have the original smallstate switch just need to know the correct color wire for each corresponding switch terminal. Thanks.

So for the bulbs: Brake=18w, Tail=5W and Headlight=25/25W?

I was able to get a somewhat better resolution version of the smallstate manual and manually enhanced the wire locations and numbers. I think its right but can someone check my math? Thanks.

Yes. That is how mine is wired and everything works just fine.

You are correct, sir.

I don't know why scooter help hasn't done a 1966-1967 "USA spec" diagram.

Your enhanced switch wiring image is good! 👍

+1

I found that the majority of the wiring to my stator was rotten and needed to be replaced. While I was in there, I decided to gen up a color-coded diagram since the Smallstate VMA1T is somewhat different from the Vespa variant. If I have some time, I'll redraw the whole harness as scooterhelp doesn't seem to have this one.

Fun fact: The wires coming off the coils themselves are also enameled underneath the colored plastic insulation (makes sense, it's magnet wire). Got to scrape off the enamel before you can solder!

All together in one spot. Again, someone please check my math.

looks good to me.

Nice work

It could be expanded to North American models 1966-1968 without battery. You could add a blue dotted line (from terminal 4) and a speedometer bulb to cover the Sears Sprint VLB and the SS180 VSC. Probably more helpful details for those who can't find the diagram for their model that fits in that timeframe.

Just a thought.

It is nice that you made the graphic at all.

Like this?

The SS has an external coil.

As do the VA15T and the Sears Sprint. More diagrams! But the "four wire" stator arrangement is the same. The more information the better.

As a side note: it's super simple to upgrade the internal HT coil to an external on the smallstates, 90's etc.

I'm assuming someone has the technology to put these new diagrams up on scooterhelp?

The SS diagram is from ScooterHelp.

Ludes (and yes, I'm old enough to remember them): What's the benefit of an external ignition coil?

It's about reliability and parts availability. In my case the internal HT coil was damaged and I had a sacrificial stator to rob the LT coil and external HT coil from. This was in the before times, so no one click ordering.

I wouldn't suggest converting for no reason if there's nothing wrong.

Here's the primary coil:
https://www.scootermercato.com/Scooter-Parts/Stator-Coils/91491

And this HT coil (the more correct looking CEAB / Femsa style are out of stock):
https://www.scootermercato.com/Scooter-Parts/Ignition-Coils/132299

OK Team, my brake light is still kicking my ass.

I rewired the stator. Headlight (High and low beam), tail light, horn and kill switch all work properly. When I hook a 9 volt AC power supply to the disconnected blue and black wire in the terminal block, and press the brake pedal, the brake light turns on. Brake light coil shot? Anyone have a test procedure?

That sounds correct. To turn off the various circuits they get shorted to ground basically killing the power. Don't over think it. The black is still a ground path, but not like you're probably used to. I think I you're chasing a problem that doesn't exist.

Basically the black (ground) wire is there to both provide the ground for the bulbs / horn and is also the ground path to short the blue/green/red/yellow wires when they're not needed ( "off").

Put a meter on the blue wire from the stator. Running...

Duh? That way I could tell if was it was generating electricity! I'm such a shit for brains sometimes.

The blue side of the coil grounds through the pilot, speedo and tail bulbs so they have to be in place. I don't know if they all have to be, maybe just one... The yellow side grounds through the brake pedal or bulb. I don't understand this at all but maybe I have it all wrong.

Yeah, true statement.

The wiring schematic tells the story, it's up to you to understand the context of the "words" as written. You haven't read the story, you glanced at it.

Please elucidate... I have been glancing for years.
I have a green/yellow coil with two grounded tails. Two separate windings on a common core. I have a blue/yellow with no apparent grounds.

That's correct. But the discussion had moved to the wiring on the chassis, specifically the smallstate and others with no yellow from the stator.

Everybody gets a ground in circuit to "turn off" power from the coils on the stator.

Just to elucidate... 😉

13.1 VAC at the disconnected blue wire in the terminal black. No brake light. On a whim, I took the tail light assembly off the frame. Brake light works off the frame. Put the tail light assembly back on the frame and no brake light. WTFO!?!

Reassembled the tail light assembly with neoprene gromets between the frame and the bolts.....brake light works! Must have a stray ground somewhere.

Strange, but a solution is a solution. Glad you got it to work.

It sounds like you've got the black and blue wires reversed at the taillight. It would do exactly what you described when the lamp housing would earth to the chassis and be "all better" when isolated.

At least the MM is easy to remove.