Modern Vespa

All,
As you know finding Neutral indicator switches is nearly impossible these days. However, I found a possible source on Amazon for the neutral indication switch that controls the Neutral light on the speedometer on early U.S. Spec P Series. There is one problem though. The switch is "Normally Closed". I purchased a set which came from China. These switches are dimensionally exact to the originals and the quality seems very good! However I tested one with a volt meter and quickly discovered they won't work. The early P Series came with a "Normally Open" switch.
My solution is to replace the plastic cam in the gear selector box with a new 3-D printed one. The new cam would simply need its profile modified. The OEM plastic cam pushes on the switch button only when it's Neutral. To make this switch work, we need a cam that will push the button in all gears except Neutral. So it will need a low spot in the cam profile for Neutral only. I suppose you could make the "low spot" in an existing cam and screw the switch in further than normal so the button is pushed in all gears. If anyone would like to donate a cam for experimental purposes please let me know.

Any takers?

Hec

Possibly a public library in Omaha will have one? Or a maker space at UNO?

But the step before that is making a 3-D model to print, using something like sketchup. I think this could be an ok way to prototype, but then you have to print it with a polymer that will hold up to wear and tear.

you could add a relay to invert the signal.

That's a way better idea! I need to figure out how to wire a relay so that 12v + breaks the circuit and turns off the N light.

I removed the plastic cam and sketched up something that might work. I like the relay idea much better!

Hec

I'm of no help, but I'm watching closely

Here's a link to how to wire a relay to change over Normally Open to Normally Closed.
https://www.electronicshub.org/relay-wiring-diagram/

You would need a 5-pin relay, and you would wire the Neutral indicator switch to the coil pin 85 as shown, and wire the bulb to the relay NC pin 87A as for Light 2 in this diagram. Pin 87 and Light 1 are not used.

Ya beat me to it! A Normally Closed Relay is needed. This is what I came up with. It should work! So if you want to have that Neutral indication light working again and your OEM switch is broke, this is your fix. And its Cheap!

Normally Closed Relay
https://www.ebay.com/itm/164140488985?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=gx2nq6u2rgi&sssrc=2349624&ssuid=lT7ds1Y6TsS&var=&widget_ver=artemis&media=COPY

Normally Closed Switch
https://www.amazon.com/dp/B07WK7DC83?psc=1&ref=ppx_yo2ov_dt_b_product_details


I'm lucky my switch still works! I went ahead and changed the title of this thread to help others search this topic in the future.

I've been looking for a solution as well, for the hell of it*.
But in my case I don't have a stock selector box.

KR Automation boxes. Close to an EFL upgrade from my experiences. It's $$

I'm going to put a trigger somewhere up in the headset on the two P's. So far two switch tries have failed

*Ride a while and there's no mistaking neutral. Feels like mush.

What if you call it an "in gear" indicator instead of a "neutral" indicator?

Keep up the work for science! If you do give up, it looks like they have some switches in stock.

https://www.scooterwest.com/p-neutral-switch-for-1977-1980-p125x-p200e-126939.html

I heard those SW aftermarket switches would strip easily as the housings were made from plastic. I have not tried them.

LML had a basic solution where the butterfly-neutral-pin would touch a contact on the cam, and close the circuit. A spring holds tension for the cam to press against the pin. I have one of these as a spare but have never tried it. Very simple but not sure of the reliability. I have never had a Stella so I cannot comment on the efficacy or reliability of the neutral light. Perhaps some Stella owners might chime in.

and the have the rubber cap too!

I have a SW switch. It came with my P125X. It's never been installed. The OEM switch was still installed when I got it. I worked on the switch and got it working again. I think I'd go with my solution over the plastic SW switch because the metal switch appears to be more robust.

Hec